sched: Fix comment for requeue_rt_entity

Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1321117677-3282-1-git-send-email-richard@nod.at
Signed-off-by: Ingo Molnar <mingo@elte.hu>