[ARM] Marvell OpenRD-Ultimate machine support

This patch adds support for the OpenRD Ultimate machine (could be found
at http://www.arm.linux.org.uk/developer/machines/list.php?id=2884

)

Signed-off-by: Dmytro Milinevskyy <milinevskyy@gmail.com>
Acked-by: Lennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: Nicolas Pitre <nico@fluxnic.net>