gpu/vulkan: Move dereference after null check

src/gpu/vulkan/SDL_gpu_vulkan.c

@@ -9521,7 +9521,8 @@ static SDL_GPUCommandBuffer *VULKAN_AcquireCommandBuffer(
     VulkanCommandBuffer *commandBuffer =
         VULKAN_INTERNAL_GetInactiveCommandBufferFromPool(renderer, threadID);
 
-    commandBuffer->descriptorSetCache = VULKAN_INTERNAL_AcquireDescriptorSetCache(renderer);
+    DescriptorSetCache *descriptorSetCache =
+        VULKAN_INTERNAL_AcquireDescriptorSetCache(renderer);
 
     SDL_UnlockMutex(renderer->acquireCommandBufferLock);
 
@@ -9529,6 +9530,8 @@ static SDL_GPUCommandBuffer *VULKAN_AcquireCommandBuffer(
         return NULL;
     }
 
+    commandBuffer->descriptorSetCache = descriptorSetCache;
+
     // Reset state
 
     commandBuffer->currentComputePipeline = NULL;