drm/xe: Add exec_queue.sched_props.job_timeout_ms

The purpose here is to allow to optimize exec_queue_set_job_timeout()
in follow-on patch.  Currently it does q->ops->set_job_timeout(...).
But we'd like to apply exec_queue_user_extensions much earlier and
q->ops cannot be called before __xe_exec_queue_init().

It will be much more efficient to instead only have to set
q->sched_props.job_timeout_ms when applying user extensions. That value
will then be used during q->ops->init().

Signed-off-by: Brian Welty <brian.welty@intel.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>