This commit adds the description of the CPU config registers in the
Armada 370 and Armada XP Device Tree. Since the registers are in fact
different between the two SoCs, a different compatible string is used.

Note that the Armada 370 node is currently unused, but it is
nonetheless added for consistency with the addition on the Armada XP
side.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>