sched: Use task_rq_unlock() in __sched_setscheduler()

It seems there's no specific reason to open-code it.  I guess
commit 0122ec5b02f76 ("sched: Add p->pi_lock to task_rq_lock()")
simply missed it.  Let's be consistent with others.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1341647342-6742-1-git-send-email-namhyung@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

kernel/sched/core.c

@@ -4340,9 +4340,7 @@ recheck:
 	 */
 	if (unlikely(policy == p->policy && (!rt_policy(policy) ||
 			param->sched_priority == p->rt_priority))) {
-
-		__task_rq_unlock(rq);
-		raw_spin_unlock_irqrestore(&p->pi_lock, flags);
+		task_rq_unlock(rq, p, &flags);
 		return 0;
 	}