ARM: mvebu: set aliases for ethernet controllers

These aliases are used when feeding the DT from ATAGS to set the
devices MAC addresses.

Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>