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

Replace the wrmsr/rdmrs_on_cpu() calls in the hotplug callbacks as they are
guaranteed to be invoked on the incoming/outgoing cpu.
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Tested-by: NSrinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: NZhang Rui <rui.zhang@intel.com>