realtek: switch Zyxel XGS1210 to NVMEM
These devices contain a single MAC address in the U-Boot environment.
Set it as eth0 and label MAC in device tree.
To maintain the current state, the 02_network script still sets
individual port MAC addresses and the bridge MAC address.
Signed-off-by: Jan Hoffmann <[email protected]>
Link: https://github.com/openwrt/openwrt/pull/22024
Signed-off-by: Robert Marko <[email protected]>