fix: only enable validation layer when renderdoc profiling is enabled

Author: inspireMeNow

src/gpu.cpp

@@ -27,7 +27,11 @@
 
 // There is known issue that vkDestroyDebugUtilsMessengerEXT crash on exit when vulkan validation layer enabled
 // upstream fix https://github.com/KhronosGroup/Vulkan-Loader/pull/539
+#if NCNN_ENABLE_RENDERDOC_PROFILING
 #define ENABLE_VALIDATION_LAYER 1
+#else
+#define ENABLE_VALIDATION_LAYER 0
+#endif
 
 #if NCNN_ENABLE_RENDERDOC_PROFILING