do only invalid hashes instead of all textures on loading

this is a hack, but only the gpu thread is allowed to call ogl commands
suggestion: create an unused texture cache, so we can move all textures there

Source/Core/VideoCommon/Src/TextureCacheBase.h

@@ -106,6 +106,7 @@ public:
 	static void Cleanup();
 
 	static void Invalidate();
+	static void InvalidateHashes();
 	static void InvalidateRange(u32 start_address, u32 size);
 	static void MakeRangeDynamic(u32 start_address, u32 size);
 	static void ClearRenderTargets();	// currently only used by OGL