nvflinger: Signal BufferQueue native handle event.

- This gets BOTW booting.

src/core/hle/service/nvflinger/buffer_queue.cpp

@@ -14,6 +14,7 @@ namespace NVFlinger {
 
 BufferQueue::BufferQueue(u32 id, u64 layer_id) : id(id), layer_id(layer_id) {
     native_handle = Kernel::Event::Create(Kernel::ResetType::OneShot, "BufferQueue NativeHandle");
+    native_handle->Signal();
 }
 
 void BufferQueue::SetPreallocatedBuffer(u32 slot, IGBPBuffer& igbp_buffer) {