ARM: mvebu: export PMSU idle enter/exit functions

The PMSU idle enter/exit functions will be needed for the CPU hotplug
implementation on Armada XP, so this commit removes their static
qualifier, and adds the appropriate prototypes in armada-370-xp.h.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Link: https://lkml.kernel.org/r/1401481098-23326-4-git-send-email-thomas.petazzoni@free-electrons.com


Signed-off-by: Jason Cooper <jason@lakedaemon.net>