ARM: mvebu: add initial support for the Armada 380/385 SOCs

This commit adds the basic support for the Armada 380 and Armada 385
SOCs. These SoCs share most of their IP with the Armada 370/XP
SoCs. The main difference is the use of a Cortex A9 CPU instead of the
PJ4B CPU. The Armada 380 is a single core Cortex-A9, while the Armada
385 is a dual-core Cortex-A9.

The support is introduced in board-v7.c, together with Armada 370/XP,
but a separate DT structure is added, because Armada 38x will need a
different set of SMP operations when the SMP support is introduced.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>