timers, sched: Correct the comments for tick_sched_timer()

In the comments of function tick_sched_timer(), the sentence
"timer->base->cpu_base->lock held" is not right.

In function __run_hrtimer(), before call timer->function(),
the cpu_base->lock has been unlocked.
Signed-off-by: Nliu chuansheng <chuansheng.liu@intel.com>
Cc: fei.li@intel.com
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1351098455.15558.1421.camel@cliu38-desktop-buildSigned-off-by: NIngo Molnar <mingo@kernel.org>

kernel/time/tick-sched.c

@@ -794,7 +794,7 @@ void tick_check_idle(int cpu)
 #ifdef CONFIG_HIGH_RES_TIMERS
 /*
  * We rearm the timer until we get disabled by the idle code.
- * Called with interrupts disabled and timer->base->cpu_base->lock held.
+ * Called with interrupts disabled.
  */
 static enum hrtimer_restart tick_sched_timer(struct hrtimer *timer)
 {