sched: simplify sched_class::yield_task()

	void (*enqueue_task) (struct rq *rq, struct task_struct *p, int wakeup);

	void (*dequeue_task) (struct rq *rq, struct task_struct *p, int sleep);

	void (*yield_task) (struct rq *rq, struct task_struct *p);

	void (*yield_task) (struct rq *rq);

	void (*check_preempt_curr) (struct rq *rq, struct task_struct *p);

	struct rq *rq = this_rq_lock();

	schedstat_inc(rq, yld_cnt);

	current->sched_class->yield_task(rq, current);

	current->sched_class->yield_task(rq);

	/*

	 * Since we are going to call schedule() anyway, there's

 *

 * If compat_yield is turned on then we requeue to the end of the tree.

 */

static void yield_task_fair(struct rq *rq, struct task_struct *p)

static void yield_task_fair(struct rq *rq)

{

	struct cfs_rq *cfs_rq = task_cfs_rq(p);

	struct cfs_rq *cfs_rq = &rq->cfs;

	struct rb_node **link = &cfs_rq->tasks_timeline.rb_node;

	struct sched_entity *rightmost, *se = &p->se;

	struct sched_entity *rightmost, *se = &rq->curr->se;

	struct rb_node *parent;

	/*

		 * Dequeue and enqueue the task to update its

		 * position within the tree:

		 */

		dequeue_entity(cfs_rq, &p->se, 0);

		enqueue_entity(cfs_rq, &p->se, 0);

		dequeue_entity(cfs_rq, se, 0);

		enqueue_entity(cfs_rq, se, 0);

		return;

	}

}

static void

yield_task_rt(struct rq *rq, struct task_struct *p)

yield_task_rt(struct rq *rq)

{

	requeue_task_rt(rq, p);

	requeue_task_rt(rq, rq->curr);

}

/*