tick-sched: change the cpu that updates rq_stats

It can happen that the scheduler tick stops on cpu 0 but keeps
running on some other cpu. Make the cpu in-charge of updating
the jiffies also update the rq_stats.

Change-Id: Idb1a8132bd96500c68c516b4a99663965cec28e1
Signed-off-by: Amar Singhal <asinghal@codeaurora.org>