Make efb2tex behave more like efb2ram.

Instead of having special case code for efb2tex that ignores hashes,
the only diffence between efb2tex and efb2ram now is that efb2tex
writes zeros to the memory instead of actual texture data.

Though keep in mind, all efb2tex copies will have hashes of zero as
their hash.

Source/Core/VideoCommon/TextureCacheBase.h

@@ -111,7 +111,7 @@ public:
 		u32 NumBlocksY() const;
 		u32 CacheLinesPerRow() const;
 
-		void Memset(u8* ptr, u32 tag);
+		void Zero(u8* ptr);
 	};
 
 	virtual ~TextureCache(); // needs virtual for DX11 dtor