mvebu: add inital support for Marvell Armada XP/370 SoCs

This brings in the initial support for the Marvell Armada XP/370 SoCs.
Successfully tested on RD-A370-A1 and DB-MV784MP-GP boards the following
interfaces:

- Ethernet
- SDIO
- GPIOs
- SATA

Signed-off-by: Florian Fainelli <florian@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt@35058 3c298f89-4303-0410-b956-a3cf2f4a3e73
kernel: adjust orion/kirkwood packages to also build for mvebu target

Armada XP/370 boards share these hardware blocks with Orion and Kirkwood
SoCs.

Signed-off-by: Florian Fainelli <florian@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt@35059 3c298f89-4303-0410-b956-a3cf2f4a3e73
kernel: make kmod-of-i2c available for the mvebu target

Signed-off-by: Florian Fainelli <florian@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt@35060 3c298f89-4303-0410-b956-a3cf2f4a3e73
kernel: add kmod-mvsdio MMC host controller for Marvell targets

Signed-off-by: Florian Fainelli <florian@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt@35061 3c298f89-4303-0410-b956-a3cf2f4a3e73