ARM: mvebu: Register notifier callback for the cpuidle transition

In order to have well encapsulated code, we use notifier callbacks for
CPU_PM_ENTER and CPU_PM_EXIT inside the mvebu power management code.

Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Link: https://lkml.kernel.org/r/1397488214-20685-10-git-send-email-gregory.clement@free-electrons.com
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>