anv: properly handle fence import of sync_fd = -1

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Fixes: 43e8808b82b9eb ("anv: Add support for the SYNC_FD handle type for fences")
Reviewed-by: Tapani Pälli <tapani.palli@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5964>
1 file changed