drm/sched: Rename drm_sched_run_job_queue_if_ready and clarify kerneldoc

"If ready" is not immediately clear what it means - is the scheduler
ready or something else? Drop the suffix, clarify kerneldoc, and employ
the same naming scheme as in drm_sched_run_free_queue:

 - drm_sched_run_job_queue   - enqueues if there is something to enqueue
                               *and* scheduler is ready (can queue)
 - __drm_sched_run_job_queue - low-level helper to simply queue the job

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Luben Tuikov <ltuikov89@gmail.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231102105538.391648-5-tvrtko.ursulin@linux.intel.com
Reviewed-by: Luben Tuikov <ltuikov89@gmail.com>
Signed-off-by: Luben Tuikov <ltuikov89@gmail.com>