fix use after free

src/Refresh_Driver_Vulkan.c

@@ -8067,6 +8067,7 @@ static void VULKAN_INTERNAL_ResetCommandBuffer(
 	}
 
 	SDL_free(commandBuffer->transferBuffers);
+	commandBuffer->transferBuffers = NULL;
 	commandBuffer->transferBufferCount = 0;
 
 	commandBuffer->submitted = 0;