sched/core: Remove the pointless BUG_ON(!task) from wake_up_q()

container_of() can never return NULL - so don't check for it pointlessly.

[ mingo: Twiddled the changelog. ]
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210510161522.GA32644@redhat.com

kernel/sched/core.c

@@ -585,7 +585,6 @@ void wake_up_q(struct wake_q_head *head)
 		struct task_struct *task;
 
 		task = container_of(node, struct task_struct, wake_q);
-		BUG_ON(!task);
 		/* Task can safely be re-inserted now: */
 		node = node->next;
 		task->wake_q.next = NULL;