sched: Remove debugging check

Linus reported that the new warning introduced by commit f26f9aff6aaf
"Sched: fix skip_clock_update optimization" triggers. The need_resched
flag can be set by other CPUs asynchronously so this debug check is
bogus - remove it.

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
LKML-Reference: <AANLkTinJ8hAG1TpyC+CSYPR47p48+1=E7fiC45hMXT_1@mail.gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

kernel/sched.c

@@ -4128,7 +4128,6 @@ need_resched_nonpreemptible:
 		rq->nr_switches++;
 		rq->curr = next;
 		++*switch_count;
-		WARN_ON_ONCE(test_tsk_need_resched(next));
 
 		context_switch(rq, prev, next); /* unlocks the rq */
 		/*