fix compile warning when meson build

- Fix compile warning:
  [-Werror=unused-variable], [-Werror=sign-compare] and
  deprecated INSTANTIATE_TEST_CASE_P

Signed-off-by: Harvey.Wu <Harvey.Wu@quantatw.com>
Change-Id: If8713f0b938cd5306bbe19a9078731db0c3667dc
diff --git a/dbus/dbusconfiguration.cpp b/dbus/dbusconfiguration.cpp
index ef990c9..8871dfb 100644
--- a/dbus/dbusconfiguration.cpp
+++ b/dbus/dbusconfiguration.cpp
@@ -258,7 +258,7 @@
 }
 
 void populatePidInfo(
-    sdbusplus::bus_t& bus,
+    [[maybe_unused]] sdbusplus::bus_t& bus,
     const std::unordered_map<std::string, DbusVariantType>& base,
     conf::ControllerInfo& info, const std::string* thresholdProperty,
     const std::map<std::string, conf::SensorConfig>& sensorConfig)
diff --git a/dbus/dbuspassive.cpp b/dbus/dbuspassive.cpp
index 182a9a5..41047a1 100644
--- a/dbus/dbuspassive.cpp
+++ b/dbus/dbuspassive.cpp
@@ -331,7 +331,8 @@
     return 0;
 }
 
-int dbusHandleSignal(sd_bus_message* msg, void* usrData, sd_bus_error* err)
+int dbusHandleSignal(sd_bus_message* msg, void* usrData,
+                     [[maybe_unused]] sd_bus_error* err)
 {
     auto sdbpMsg = sdbusplus::message_t(msg);
     DbusPassive* obj = static_cast<DbusPassive*>(usrData);
diff --git a/dbus/dbusutil.hpp b/dbus/dbusutil.hpp
index 5012af0..49ec859 100644
--- a/dbus/dbusutil.hpp
+++ b/dbus/dbusutil.hpp
@@ -22,7 +22,7 @@
 
     template <typename T>
     std::enable_if_t<!std::is_arithmetic<T>::value, double>
-        operator()(const T& t) const
+        operator()([[maybe_unused]] const T& t) const
     {
         throw std::invalid_argument("Cannot translate type to double");
     }