x86/mce/therm_throt: Convert to hotplug state machine

Install the callbacks via the state machine and let the core invoke
the callbacks on the already online CPUs.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: rt@linuxtronix.de
Cc: Borislav Petkov <bp@alien8.de>
Cc: linux-edac@vger.kernel.org
Link: http://lkml.kernel.org/r/20161117183541.8588-2-bigeasy@linutronix.de


Signed-off-by: Thomas Gleixner <tglx@linutronix.de>