For now this calls cpu_idle(), but in the long run we want to move the
cpu bringup code to the core and therefor we add a state argument.

Signed-off-by: Thomas Gleixner
Cc: Linus Torvalds
Cc: Rusty Russell
Cc: Paul McKenney
Cc: Peter Zijlstra
Reviewed-by: Cc: Srivatsa S. Bhat
Cc: Magnus Damm
Link: http://lkml.kernel.org/r/20130321215233.583190032@linutronix.de
Signed-off-by: Thomas Gleixner