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/MainBase.cpp

@@ -203,7 +203,7 @@ void VideoBackendHardware::DoState(PointerWrap& p)
 
 		// Clear all caches that touch RAM
 		// (? these don't appear to touch any emulation state that gets saved. moved to on load only.)
-		TextureCache::Invalidate();
+		TextureCache::InvalidateHashes();
 		VertexLoaderManager::MarkAllDirty();
 	}
 }