ia64/salinfo: Convert to hotplug state machine

ia64/salinfo: 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>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-ia64@vger.kernel.org
Cc: kbuild test robot <lkp@intel.com>
Cc: rt@linutronix.de
Cc: kbuild-all@01.org
Link: http://lkml.kernel.org/r/20161103173128.xuulg4nius46dng5@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>