vulkan/wsi: Signal semaphores and fences from the dma-buf

vulkan/wsi: Signal semaphores and fences from the dma-buf

Instead of attempting to signal based on the memory object, use the new
DMA_BUF_IOCTL_EXPORT_SYNC_FILE to get a sync_file for the dma-buf and
use that to signal the semaphore or fence.  Because this happens before
we transfer ownership back to the driver, the resulting sync_file should
only contain dma_fences from the compositor and/or display and shouldn't
be mixed up with the driver in any way.  This gives us a real semaphore
and fence (as opposed to the dummy objects we've used int the past)
without over-synchronization.

Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4037>