fix(system_monitor): fix build error on tegra platform (tier4#869)

* fix(system_monitor): fix build error on tegra platform

Signed-off-by: Shark Liu <shark.liu@autocore.ai>

* ci(pre-commit): autofix

* Update system/system_monitor/src/gpu_monitor/tegra_gpu_monitor.cpp

Co-authored-by: Shark Liu <shark.liu@autocore.ai>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Daisuke Nishimatsu <42202095+wep21@users.noreply.github.com>

system/system_monitor/src/gpu_monitor/tegra_gpu_monitor.cpp

@@ -127,8 +127,10 @@ void GPUMonitor::checkUsage(diagnostic_updater::DiagnosticStatusWrapper & stat)
   }
 }
 
-void GPUMonitor::checkThrottling(diagnostic_updater::DiagnosticStatusWrapper & stat)
+void GPUMonitor::checkThrottling(
+  [[maybe_unused]] diagnostic_updater::DiagnosticStatusWrapper & stat)
 {
+  // Please remove the [[maybe_unused]] tag after implementation, it's a temp build fix
   // TODO(Fumihito Ito): implement me
 }