ath79: mikrotik: use base mac on lan for RBwAPG-5HacT2HnD
The Mikrotik RBwAPG-5HacT2HnD has only a single ethernet interface
(lan), and the vendor uses the base (label) MAC address for it.
Signed-off-by: Bjoern Dobe <[email protected]>
[commit title/message improvement]
Signed-off-by: Adrian Schmutzler <[email protected]>