smp/cfd: Convert core to hotplug state machine

smp/cfd: Convert core to hotplug state machine

Install the callbacks via the state machine. They are installed at runtime so
smpcfd_prepare_cpu() needs to be invoked by the boot-CPU.

Signed-off-by: Richard Weinberger <[email protected]>
[ Added the dropped CPU dying case back in. ]
Signed-off-by: Richard Cochran <[email protected]>
Signed-off-by: Anna-Maria Gleixner <[email protected]>
Reviewed-by: Sebastian Andrzej Siewior <[email protected]>
Cc: Davidlohr Bueso <dave@stgolabs>
Cc: Linus Torvalds <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Rasmus Villemoes <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>