x86: add all ports to the Gowin 1U default network config

x86: add all ports to the Gowin 1U default network config

Commit e52c57bb1b30375e0bcc5523db76a672a4a8b4a4 renamed all
network ports to match the faceplate of the Gowin 1U Rack
Mount Server and added the br-lan bridge for the eth* ports.

This commit adds the PoE port to the br-lan bridge and a
br-wan bridge for the two SFP ports so that all ports are
part of the default network configuration.

Signed-off-by: Til Kaiser <mail@tk154.de>
Link: https://github.com/openwrt/openwrt/pull/16965
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>