Fix unreferenced parameter warning in glog stub (#14708)

* Fix warning in glog stub

* Change files

Author: acoates-ms

change/react-native-windows-5703a6a9-97cc-48bb-b2d3-95a626c17fa1.json

@@ -0,0 +1,7 @@
+{
+  "type": "prerelease",
+  "comment": "Fix warning in glog stub",
+  "packageName": "react-native-windows",
+  "email": "[email protected]",
+  "dependentChangeType": "patch"
+}

vnext/stubs/glog/logging.h

@@ -72,7 +72,7 @@ inline std::ostream &GetNullLog() noexcept {
 #define LOG_EVERY_N(severity, n) GlogStub::GetNullLog()
 
 typedef int LogSeverity;
-inline void FlushLogFiles(LogSeverity min_severity) {}
+inline void FlushLogFiles(LogSeverity) {}
 
 #define google GlogStub
 static const int GLOG_INFO = 1;