Fix warnings for -no-feature-settings

Change-Id: I79ce0b9c5eb931e238394519ba80bf35e4ff3bf7
Reviewed-by: Tasuku Suzuki <tasuku.suzuki@qt.io>
Reviewed-by: Paul Olav Tvete <paul.tvete@qt.io>

src/corelib/global/qlibraryinfo.cpp

@@ -663,6 +663,8 @@ QStringList QLibraryInfo::platformPluginArguments(const QString &platformName)
                 + QLatin1String("Arguments");
         return settings->value(key).toStringList();
     }
+#else
+    Q_UNUSED(platformName);
 #endif // !QT_BUILD_QMAKE && !QT_NO_SETTINGS
     return QStringList();
 }

src/gui/kernel/qplatforminputcontextfactory.cpp

@@ -82,6 +82,8 @@ QPlatformInputContext *QPlatformInputContextFactory::create(const QString& key)
 
         delete ic;
     }
+#else
+    Q_UNUSED(key);
 #endif
     return 0;
 }