drm/amdgpu: remove useless condition in amdgpu_job_stop_all_jobs_on_sched()

Local variable 'rq' is initialized by an address
of field of drm_sched_job, so it does not make
sense to compare 'rq' with NULL.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Reviewed-by: Andrey Grodzovsky <[e-mail]>
Signed-off-by: Andrey Strachuk <[e-mail]>
Fixes: 7c6e68c777f1 ("drm/amdgpu: Avoid HW GPU reset for RAS.")
Signed-off-by: Alex Deucher <[e-mail]>

drivers/gpu/drm/amd/amdgpu/amdgpu_job.c

···
 	/* Signal all jobs not yet scheduled */
 	for (i = DRM_SCHED_PRIORITY_COUNT - 1; i >= DRM_SCHED_PRIORITY_MIN; i--) {
 		struct drm_sched_rq *rq = &sched->sched_rq[i];
-
-		if (!rq)
-			continue;
-
 		spin_lock(&rq->lock);
 		list_for_each_entry(s_entity, &rq->entities, list) {
 			while ((s_job = to_drm_sched_job(spsc_queue_pop(&s_entity->job_queue)))) {