sched: update_rq_clock() must skip ONE update

Prevent large wakeup latencies from being accounted to the wrong task.

Change-Id: Ie9932acb8a733989441ff2dd51c50a2626cfe5c5
Cc: <stable@vger.kernel.org>
Signed-off-by: Mike Galbraith <umgwanakikbuti@gmail.com>
CRs-Fixed: 755576
Patch-mainline: http://permalink.gmane.org/gmane.linux.kernel/1677324


Signed-off-by: Srivatsa Vaddagiri <vatsa@codeaurora.org>