timers/nohz: Fix several typos

Signed-off-by: Wei Jiangang <weijg.fnst@cn.fujitsu.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: fenghua.yu@intel.com
Link: http://lkml.kernel.org/r/1467175910-2966-2-git-send-email-weijg.fnst@cn.fujitsu.com


Signed-off-by: Ingo Molnar <mingo@kernel.org>