arm: mvebu: Update CBAR with SOC regs base

SMP-enabled Linux kernels read the CBAR register in CP15 to find
the address of the SCU registers.  After remapping internal
registers, also update the CBAR so the kernel can find them.

Signed-off-by: Kevin Smith <kevin.smith@elecsyscorp.com>
Acked-by: Stefan Roese <sr@denx.de>