MainWindow: Replace WARN_LOG with WARN_LOG_FMT

Source/Core/DolphinQt/MainWindow.cpp

@@ -325,7 +325,7 @@ void MainWindow::InitControllers()
   if (!g_controller_interface.HasDefaultDevice())
   {
     // Note that the CI default device could be still temporarily removed at any time
-    WARN_LOG(CONTROLLERINTERFACE,
+    WARN_LOG_FMT(CONTROLLERINTERFACE,
                  "No default device has been added in time. EmulatedController(s) defaulting adds"
                  " input mappings made for a specific default device depending on the platform");
   }