The gmac1 is not used and doesn't have any mac address configured. The
gmac0 has the nvmem-cells set and can actually be used to retrieve the
correct mac address.
Fixes: c7c54f3134 ("ramips: add support for Plasma Cloud PAX1800-Lite")
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Link: https://github.com/openwrt/openwrt/pull/23441
Signed-off-by: Robert Marko <robimarko@gmail.com>