sched: eliminate rq_clock() use

eliminate rq_clock() use by changing it to:

   update_rq_clock(rq)
   now = rq->clock;

identity transformation - no change in behavior.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --cc kernel/sched.c
Simple merge

diff --cc kernel/sched_fair.c
Simple merge