sched/cpuidle: reduce IPI store. Backport upstream 3.16 scheduler updates

Change-Id: I3d8ff48b2130930da00d2ddf7ff1e7913d6b49ef
Signed-off-by: Paul Reioux <reioux@gmail.com>
Voltage Control: fix minor code derp

Change-Id: I2ab6c29b4ac377d543c1351a857e63d555ef67b2
Signed-off-by: Paul Reioux <reioux@gmail.com>