mediatek: Fix setting MAC address for some devices
This fixes a previous commit breaking setting the MAC address for the
wifi devices.
Fixes: 9ed4d27fbf90 ("mediatek: filogic: fix 5G MAC address for Zyxel EX5601")
Link: https://github.com/openwrt/openwrt/pull/20100
Signed-off-by: Hauke Mehrtens <[email protected]>