arm: mm: Add support for PJ4B cpu and init routines

PJ4B is an implementation of the ARMv7 (such as the Cortex A9 for
example) released by Marvell. This CPU is currently found in
Armada 370 and Armada XP SoCs. This patch provides a support for the
specific initialization of this CPU.

Signed-off-by: Yehuda Yitschak <yehuday@marvell.com>
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>