radv/winsys: fix zero submit if no timeline semaphore support

radv/winsys: fix zero submit if no timeline semaphore support

Kernels that don't support timeline semaphores also don't support
transferring syncobjs. Use export/import instead.

Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/5845
Fixes: 967fc415fc4 ("radv: Add new submission path for use by the common sync framework.")
Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/14538>