The network configuration at first boot for TOZED ZLT S12 PRO lacks setting
up the LAN and WAN network interfaces. Address this. The WAN port is
advertised as WAN/LAN on the device and is put on LAN on stock firmware so
put it on LAN here as well.

Fixes: ce1f9fa6 ("ramips: add support for TOZED ZLT S12 PRO")
Reported-by: Andre Cruz <me@1conan.com>
Signed-off-by: Arınç ÜNAL <arinc.unal@arinc9.com>
(cherry picked from commit b61253f9)