Core: Remove UpdateFPSDisplay

This is effectively unused, as the window handles that we pass to the
GLInterface are window handles for the frame which isn't ever a real
toplevel window. Host_UpdateTitle is what actually sets the proper title
on the render window.

Source/Core/Core/Core.cpp

@@ -694,9 +694,6 @@ void UpdateTitle()
 	std::string SMessage = StringFromFormat("%s | %s", SSettings.c_str(), SFPS.c_str());
 	std::string TMessage = StringFromFormat("%s | %s", scm_rev_str, SMessage.c_str());
 
-	// Show message
-	g_video_backend->UpdateFPSDisplay(SMessage);
-
 	// Update the audio timestretcher with the current speed
 	if (soundStream)
 	{