ARM: mvebu: move Armada XP specific SMP initialization to platsmp.c

The pmsu.c driver contained an armada_xp_boot_cpu() function that sets
the boot address of a secondary CPUs and deasserts the reset. However,
the Armada 375 needs a slightly different logic, so it makes more
sense to move this code into the Armada XP specific platsmp.c.

In order to achieve this, the mvebu_pmsu_set_cpu_boot_addr() function
is exported. It will be needed for both the Armada XP and Armada 38x
SMP implementations.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Link: https://lkml.kernel.org/r/1397483648-26611-2-git-send-email-thomas.petazzoni@free-electrons.com
Signed-off-by: Jason Cooper <jason@lakedaemon.net>