Thanks to a hint from Michael Siegenthaler in 4b4fa2f9fe ("ramips:
fix ethernet MAC address on Omega2"), the label MAC address of
the Onion Omega 2(+) can be set based on its documentation [1].
[1] https://docs.onion.io/omega2-docs/mac-address.html
Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>