graphics: write small GPU-written tiled images back to guest memory behind --readback-tiled-images

Co-authored-by: Dimitar Vagalinski <275970482+overlordxrz-source@users.noreply.github.com>
Co-authored-by: Mr. Big Britches <111622360+MrBigBritches@users.noreply.github.com>

src/graphics/host_gpu/renderer/cache/textureCache.h

@@ -180,6 +180,7 @@ private:
 	uint64_t         m_gc_tick                = 0;
 	mutable uint32_t m_image_query_epoch      = 0;
 	bool             m_readback_linear_images = false;
+	bool             m_readback_tiled_images  = false;
 
 	friend struct TextureCacheTestAccess;
 	friend class BufferCache;