Handle Netgear ProSecure UTM25

Handle Netgear ProSecure UTM25

This makes the system recognize and configure Netgear ProSecure UTM25.
Of the network ports, LAN1-4 and WAN1 are functional. WAN2 does not work
for some reason. Even though WAN1 has a separate link to the SoC, the
connection appears to go through the same switch that the LAN ports use.
At the moment, the system relies on U-Boot to set up the switch so that
the LAN and WAN segments stay separate.

Initial diff and input from Thaison Nguyen, thank you!