Revert "drm/scheduler: track GPU active time per entity"

This reverts commit df622729dd as it introduces a use-after-free,
which isn't easy to fix without going back to the design drawing board.

Reported-by: Danilo Krummrich <dakr@redhat.com>
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>

drivers/gpu/drm/scheduler/sched_main.c

@@ -906,12 +906,6 @@ drm_sched_get_cleanup_job(struct drm_gpu_scheduler *sched)
 
 	spin_unlock(&sched->job_list_lock);
 
-	if (job) {
-		job->entity->elapsed_ns += ktime_to_ns(
-			ktime_sub(job->s_fence->finished.timestamp,
-				  job->s_fence->scheduled.timestamp));
-	}
-
 	return job;
 }
 

include/drm/gpu_scheduler.h

@@ -228,13 +228,6 @@ struct drm_sched_entity {
 	 */
 	struct rb_node			rb_tree_node;
 
-	/**
-	 * @elapsed_ns:
-	 *
-	 * Records the amount of time where jobs from this entity were active
-	 * on the GPU.
-	 */
-	uint64_t elapsed_ns;
 };
 
 /**