oprofile/timer: Convert to hotplug state machine

oprofile/timer: Convert to hotplug state machine

Install the callbacks via the state machine and let the core invoke
the callbacks on the already online CPUs.
Since the online target runs always on the target CPU we can drop
smp_call_function_single(). The functions is invoked with interrupts off to
keep the old calling convention. If the maintainer things that this function
can be called with interrupts enabled then it can be removed :)

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Robert Richter <rric@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: oprofile-list@lists.sf.net
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160906170457.32393-10-bigeasy@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>