Remove more unused code.

Source/Core/Common/Src/Timer.cpp

@@ -97,12 +97,6 @@ void Timer::AddTimeDifference()
 	m_StartTime += GetTimeDifference();
 }
 
-// Wind back the starting time to a custom time
-void Timer::WindBackStartingTime(u64 WindBack)
-{
-	m_StartTime += WindBack;
-}
-
 // Get the time elapsed since the Start()
 u64 Timer::GetTimeElapsed()
 {

Source/Core/Common/Src/Timer.h

@@ -35,7 +35,6 @@ public:
 	// The time difference is always returned in milliseconds, regardless of alternative internal representation
 	u64 GetTimeDifference();
 	void AddTimeDifference();
-	void WindBackStartingTime(u64 WindBack);
 
 	static void IncreaseResolution();
 	static void RestoreResolution();