gpu: skip drains for CPU-only memory unmaps

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

@@ -61,6 +61,7 @@ public:
 	                                        uint32_t packed_clear);
 	void               InvalidateMemory(uint64_t address, uint64_t size);
 	void               InvalidateMemoryFromGPU(uint64_t address, uint64_t size);
+	[[nodiscard]] bool IsRegionRegistered(uint64_t address, uint64_t size);
 
 	[[nodiscard]] bool IsMeta(uint64_t address);
 	[[nodiscard]] bool IsMetaCleared(uint64_t address, uint32_t slice);