Add tick_nohz_{stop,restart}_sched_tick to idle loop in prepartion for turning
on dynticks.  These are just noops until NO_HZ is enabled.
Signed-off-by: NChris Wright <chrisw@sous-sol.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NArjan van de Ven <arjan@linux.intel.com>