update parallel rdp

parallel-rdp-standalone/vulkan/fence.cpp

@@ -36,7 +36,7 @@ FenceHolder::~FenceHolder()
 	}
 }
 
-VkFence FenceHolder::get_fence() const
+const VkFence &FenceHolder::get_fence() const
 {
 	return fence;
 }
@@ -45,11 +45,10 @@ void FenceHolder::wait()
 {
 	auto &table = device->get_device_table();
 
-#ifdef GRANITE_VULKAN_MT
 	// Waiting for the same VkFence in parallel is not allowed, and there seems to be some shenanigans on Intel
 	// when waiting for a timeline semaphore in parallel with same value as well.
 	std::lock_guard<std::mutex> holder{lock};
-#endif
+
 	if (observed_wait)
 		return;