clockevents: Make tick handover explicit

clockevents_notify() is a leftover from the early design of the
clockevents facility. It's really not a notification mechanism,
it's a multiplex call. We are way better off to have explicit
calls instead of this monstrosity.

Split out the tick_handover call and invoke it explicitely from
the hotplug code. Temporary solution will be cleaned up in later
patches.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[ Rebase ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1658173.RkEEILFiQZ@vostro.rjw.lan
Signed-off-by: Ingo Molnar <mingo@kernel.org>

kernel/cpu.c

@@ -339,6 +339,8 @@ static int __ref take_cpu_down(void *_param)
 		return err;
 
 	cpu_notify(CPU_DYING | param->mod, param->hcpu);
+	/* Give up timekeeping duties */
+	tick_handover_do_timer();
 	/* Park the stopper thread */
 	kthread_park(current);
 	return 0;