vk_update_descriptor: Properly initialize payload on the update descriptor queue

src/video_core/renderer_vulkan/vk_update_descriptor.cpp

@@ -15,7 +15,9 @@
 namespace Vulkan {
 
 VKUpdateDescriptorQueue::VKUpdateDescriptorQueue(const Device& device_, VKScheduler& scheduler_)
-    : device{device_}, scheduler{scheduler_} {}
+    : device{device_}, scheduler{scheduler_} {
+    payload_cursor = payload.data();
+}
 
 VKUpdateDescriptorQueue::~VKUpdateDescriptorQueue() = default;