FPSCounter: Change Update's return type to void

Its returned value is never used.

Source/Core/VideoCommon/FPSCounter.cpp

@@ -26,7 +26,7 @@ void FPSCounter::LogRenderTimeToFile(u64 val)
 	m_bench_file << val << std::endl;
 }
 
-int FPSCounter::Update()
+void FPSCounter::Update()
 {
 	if (m_update_time.GetTimeDifference() >= FPS_REFRESH_INTERVAL)
 	{
@@ -43,5 +43,4 @@ int FPSCounter::Update()
 	}
 
 	m_counter++;
-	return m_fps;
 }

Source/Core/VideoCommon/FPSCounter.h

@@ -14,10 +14,9 @@ public:
 	// Initializes the FPS counter.
 	FPSCounter();
 
-	// Called when a frame is rendered. Returns the value to be displayed on
-	// screen as the FPS counter (updated every second).
-	int Update();
-	
+	// Called when a frame is rendered (updated every second).
+	void Update();
+
 	unsigned int GetFPS() const { return m_fps; }
 
 private: