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/sensorhandler.cpp b/sensorhandler.cpp
index fcfd428..3217412 100644
--- a/sensorhandler.cpp
+++ b/sensorhandler.cpp
@@ -109,7 +109,7 @@
 using sensorServiceToIdMap = std::unordered_map<std::string, std::set<uint8_t>>;
 sensorServiceToIdMap serviceToIdMap __attribute__((init_priority(101)));
 
-static void fillSensorIdServiceMap(const std::string& obj,
+static void fillSensorIdServiceMap(const std::string&,
                                    const std::string& /*intf*/, uint8_t id,
                                    const std::string& service)
 {
@@ -560,7 +560,8 @@
               uint8_t, // threshold levels states
               uint8_t  // discrete reading sensor states
               >
-    ipmiSensorGetSensorReading(ipmi::Context::ptr& ctx, uint8_t sensorNum)
+    ipmiSensorGetSensorReading([[maybe_unused]] ipmi::Context::ptr& ctx,
+                               uint8_t sensorNum)
 {
     if (sensorNum == 0xFF)
     {
@@ -825,9 +826,8 @@
     bool lowerCriticalThreshMask, bool lowerNonRecovThreshMask,
     bool upperNonCriticalThreshMask, bool upperCriticalThreshMask,
     bool upperNonRecovThreshMask, uint2_t reserved, uint8_t lowerNonCritical,
-    uint8_t lowerCritical, uint8_t lowerNonRecoverable,
-    uint8_t upperNonCritical, uint8_t upperCritical,
-    uint8_t upperNonRecoverable)
+    uint8_t lowerCritical, uint8_t, uint8_t upperNonCritical,
+    uint8_t upperCritical, uint8_t)
 {
     if (reserved)
     {
@@ -1062,7 +1062,7 @@
 
 ipmi_ret_t populate_record_from_dbus(get_sdr::SensorDataFullRecordBody* body,
                                      const ipmi::sensor::Info* info,
-                                     ipmi_data_len_t data_len)
+                                     ipmi_data_len_t)
 {
     /* Functional sensor case */
     if (isAnalogSensor(info->propertyInterfaces.begin()->first))
@@ -1266,9 +1266,9 @@
     return IPMI_CC_OK;
 }
 
-ipmi_ret_t ipmi_sen_get_sdr(ipmi_netfn_t netfn, ipmi_cmd_t cmd,
-                            ipmi_request_t request, ipmi_response_t response,
-                            ipmi_data_len_t data_len, ipmi_context_t context)
+ipmi_ret_t ipmi_sen_get_sdr(ipmi_netfn_t, ipmi_cmd_t, ipmi_request_t request,
+                            ipmi_response_t response, ipmi_data_len_t data_len,
+                            ipmi_context_t)
 {
     ipmi_ret_t ret = IPMI_CC_OK;
     get_sdr::GetSdrReq* req = (get_sdr::GetSdrReq*)request;
@@ -1312,7 +1312,7 @@
     if (it == sdrCacheMap.end())
     {
         /* Header */
-        get_sdr::SensorDataFullRecord record = {0};
+        get_sdr::SensorDataFullRecord record = {};
         get_sdr::header::set_record_id(sensor_id, &(record.header));
         record.header.sdr_version = 0x51; // Based on IPMI Spec v2.0 rev 1.1
         record.header.record_type = get_sdr::SENSOR_DATA_FULL_RECORD;
@@ -1384,10 +1384,9 @@
     return true;
 }
 
-ipmi_ret_t ipmicmdPlatformEvent(ipmi_netfn_t netfn, ipmi_cmd_t cmd,
-                                ipmi_request_t request,
-                                ipmi_response_t response,
-                                ipmi_data_len_t dataLen, ipmi_context_t context)
+ipmi_ret_t ipmicmdPlatformEvent(ipmi_netfn_t, ipmi_cmd_t,
+                                ipmi_request_t request, ipmi_response_t,
+                                ipmi_data_len_t dataLen, ipmi_context_t)
 {
     uint16_t generatorID;
     size_t count;