ARM: mvebu: export the SCU address

ARM: mvebu: export the SCU address

The SCU address will be needed in other files than board-v7.c,
especially in pmsu.c for cpuidle related activities. So this patch
adds a function that allows to retrieve the virtual address at which
the SCU has been mapped.

Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Link: https://lkml.kernel.org/r/1406120453-29291-10-git-send-email-thomas.petazzoni@free-electrons.com
Signed-off-by: Jason Cooper <jason@lakedaemon.net>