drm/xe/sched_job: prefer dma_fence_is_later

Doesn't look like we are accounting for seqno wrap. Just use
__dma_fence_is_later() like we already do for xe_hw_fence_signaled().

Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>