cleanup: Remove all warning errors for the Meson build support

Remove all the build warning to prepare for the meson build.
Meson build will be in
https://gerrit.openbmc-project.xyz/c/openbmc/phosphor-host-ipmid/+/47748

Tested:
Ipmi command works fine the cleanup.
```
$ systemctl status phosphor-ipmi-host
● phosphor-ipmi-host.service - Phosphor Inband IPMI
     Loaded: loaded (/lib/systemd/system/phosphor-ipmi-host.service; enabled; vendor preset: enabled)
     Active: active (running) since Thu 1970-01-08 21:20:56 UTC; 21s ago
   Main PID: 24987 (ipmid)
     CGroup: /system.slice/phosphor-ipmi-host.service
             └─24987 /tmp/ipmid

Jan 08 21:20:56 $HOST ipmid[24987]: Registering OEM:[0X002B79], Cmd:[0X30] for Ethstats Commands
Jan 08 21:20:56 $HOST ipmid[24987]: Registering OEM:[0X00C2CF], Cmd:[0X30] for Ethstats Commands
Jan 08 21:20:56 $HOST ipmid[24987]: Registering OEM:[0X002B79], Cmd:[0X32] for Sys Commands
Jan 08 21:20:56 $HOST ipmid[24987]: Registering OEM:[0X002B79], Cmd:[0X02] for I2C
Jan 08 21:20:56 $HOST ipmid[24987]: Registering OEM:[0X00C2CF], Cmd:[0X02] for I2C
Jan 08 21:20:56 $HOST ipmid[24987]: I2C_WHITELIST_CHECK is disabled, do not populate whitelist
Jan 08 21:20:56 $HOST ipmid[24987]: Registering OEM:[0X00C2CF], Cmd:[0X04] for Manual Zone Control
Jan 08 21:20:56 $HOST systemd[1]: Started Phosphor Inband IPMI.
Jan 08 21:20:56 $HOST ipmid[24987]: Loading whitelist filter
Jan 08 21:20:56 $HOST ipmid[24987]: Set restrictedMode = true
(reverse-i-search)`ipmi': systemctl status phosphor-^Cmi-host

$ ipmitool mc info
Device ID                 : 32
Device Revision           : 1
Firmware Revision         : 0.00
IPMI Version              : 2.0
Manufacturer ID           : 7244
Manufacturer Name         : Quanta Computer Inc.
Product ID                : 14426 (0x385a)
Product Name              : Unknown (0x385A)
Device Available          : yes
Provides Device SDRs      : yes
Additional Device Support :
    Sensor Device
    SEL Device
    FRU Inventory Device
    Chassis Device
Aux Firmware Rev Info     :
    0x00
    0x00
    0x00
    0x00
```

Change-Id: I372c9433a274bc633a24d213b7a1bc205531e33d
Signed-off-by: Willy Tu <wltu@google.com>
diff --git a/user_channel/channel_layer.cpp b/user_channel/channel_layer.cpp
index 03b1729..fb70f1e 100644
--- a/user_channel/channel_layer.cpp
+++ b/user_channel/channel_layer.cpp
@@ -29,7 +29,7 @@
     // TODO: This is not the reliable way to find the device
     // associated with ethernet interface as the channel number to
     // eth association is not done. Need to revisit later
-    struct stat fileStat = {0};
+    struct stat fileStat = {};
     std::string devName("/sys/class/net/" + getChannelName(chNum));
 
     if (stat(devName.data(), &fileStat) != 0)
diff --git a/user_channel/channel_mgmt.cpp b/user_channel/channel_mgmt.cpp
index aa746fd..afdf062 100644
--- a/user_channel/channel_mgmt.cpp
+++ b/user_channel/channel_mgmt.cpp
@@ -364,9 +364,7 @@
                 sdbusplus::bus::match::rules::member(interfaceAddedSignal) +
                 sdbusplus::bus::match::rules::argNpath(
                     0, std::string(networkIntfObjectBasePath) + "/"),
-            [&](sdbusplus::message::message& msg) {
-                initChannelPersistData();
-            });
+            [&](sdbusplus::message::message&) { initChannelPersistData(); });
 
         chInterfaceRemovedSignal = std::make_unique<sdbusplus::bus::match_t>(
             bus,
@@ -374,9 +372,7 @@
                 sdbusplus::bus::match::rules::member(interfaceRemovedSignal) +
                 sdbusplus::bus::match::rules::argNpath(
                     0, std::string(networkIntfObjectBasePath) + "/"),
-            [&](sdbusplus::message::message& msg) {
-                initChannelPersistData();
-            });
+            [&](sdbusplus::message::message&) { initChannelPersistData(); });
     }
 }
 
diff --git a/user_channel/cipher_mgmt.cpp b/user_channel/cipher_mgmt.cpp
index 8355865..5f50c86 100644
--- a/user_channel/cipher_mgmt.cpp
+++ b/user_channel/cipher_mgmt.cpp
@@ -120,10 +120,10 @@
     std::string tmpFile =
         static_cast<std::string>(cipherSuitePrivFileName) + "_tmpXXXXXX";
 
-    char tmpRandomFile[tmpFile.length() + 1];
-    strncpy(tmpRandomFile, tmpFile.c_str(), tmpFile.length() + 1);
+    std::vector<char> tmpRandomFile(tmpFile.length() + 1);
+    strncpy(tmpRandomFile.data(), tmpFile.c_str(), tmpFile.length() + 1);
 
-    int fd = mkstemp(tmpRandomFile);
+    int fd = mkstemp(tmpRandomFile.data());
     fchmod(fd, 0644);
 
     if (fd < 0)
@@ -139,16 +139,16 @@
         close(fd);
         log<level::ERR>("Error writing CS privilege level config file",
                         entry("FILE_NAME=%s", tmpFile.c_str()));
-        unlink(tmpRandomFile);
+        unlink(tmpRandomFile.data());
         return -EIO;
     }
     close(fd);
 
-    if (std::rename(tmpRandomFile, cipherSuitePrivFileName.c_str()))
+    if (std::rename(tmpRandomFile.data(), cipherSuitePrivFileName.c_str()))
     {
         log<level::ERR>("Error renaming CS privilege level config file",
                         entry("FILE_NAME=%s", tmpFile.c_str()));
-        unlink(tmpRandomFile);
+        unlink(tmpRandomFile.data());
         return -EIO;
     }
 
diff --git a/user_channel/user_mgmt.cpp b/user_channel/user_mgmt.cpp
index 1644154..c205fea 100644
--- a/user_channel/user_mgmt.cpp
+++ b/user_channel/user_mgmt.cpp
@@ -1204,8 +1204,7 @@
 void UserAccess::updatePayloadAccessInUserInfo(
     const std::array<std::array<bool, ipmiMaxChannels>, payloadsPerByte>&
         stdPayload,
-    const std::array<std::array<bool, ipmiMaxChannels>, payloadsPerByte>&
-        oemPayload,
+    const std::array<std::array<bool, ipmiMaxChannels>, payloadsPerByte>&,
     UserInfo& userInfo)
 {
     for (size_t chIndex = 0; chIndex < ipmiMaxChannels; ++chIndex)
diff --git a/user_channel/usercommands.cpp b/user_channel/usercommands.cpp
index 7af38b9..901e4a6 100644
--- a/user_channel/usercommands.cpp
+++ b/user_channel/usercommands.cpp
@@ -85,7 +85,7 @@
         return ipmi::responseParmOutOfRange();
     }
 
-    PrivAccess privAccess = {0};
+    PrivAccess privAccess = {};
     if (bitsUpdate)
     {
         privAccess.ipmiEnabled = static_cast<uint8_t>(ipmiEnabled);
@@ -207,7 +207,8 @@
  *  @returns ipmi response
  */
 ipmi::RspType<>
-    ipmiSetUserName(ipmi::Context::ptr ctx, uint6_t id, uint2_t reserved,
+    ipmiSetUserName([[maybe_unused]] ipmi::Context::ptr ctx, uint6_t id,
+                    uint2_t reserved,
                     const std::array<uint8_t, ipmi::ipmiMaxUserName>& name)
 {
     if (reserved)
@@ -238,7 +239,8 @@
  *  @returns ipmi response with 16-byte username
  */
 ipmi::RspType<std::array<uint8_t, ipmi::ipmiMaxUserName>> // user name
-    ipmiGetUserName(ipmi::Context::ptr ctx, uint6_t id, uint2_t reserved)
+    ipmiGetUserName([[maybe_unused]] ipmi::Context::ptr ctx, uint6_t id,
+                    uint2_t reserved)
 {
     if (reserved)
     {
@@ -271,9 +273,9 @@
  *  @returns ipmi response with 16-byte username
  */
 ipmi::RspType<> // user name
-    ipmiSetUserPassword(ipmi::Context::ptr ctx, uint6_t id, bool reserved1,
-                        bool pwLen20, uint2_t operation, uint6_t reserved2,
-                        SecureBuffer& userPassword)
+    ipmiSetUserPassword([[maybe_unused]] ipmi::Context::ptr ctx, uint6_t id,
+                        bool reserved1, bool pwLen20, uint2_t operation,
+                        uint6_t reserved2, SecureBuffer& userPassword)
 {
     if (reserved1 || reserved2)
     {
@@ -404,7 +406,8 @@
               >
     ipmiGetChannelAuthenticationCapabilities(ipmi::Context::ptr ctx,
                                              uint4_t chNum, uint3_t reserved1,
-                                             bool extData, uint4_t privLevel,
+                                             [[maybe_unused]] bool extData,
+                                             uint4_t privLevel,
                                              uint4_t reserved2)
 {
     uint8_t channel =
@@ -522,7 +525,7 @@
         return ipmi::responseParmOutOfRange();
     }
 
-    PayloadAccess payloadAccess = {0};
+    PayloadAccess payloadAccess = {};
     payloadAccess.stdPayloadEnables1[1] = stdPayload1SOL;
 
     return ipmi::response(ipmiUserSetUserPayloadAccess(