Add support for HPE JG926A (1920-24G-PoE+ 370W)

[evs]

Mm. I had a user PM me that they did high temp testing and no change.

Anyway I'm going to be reading/testing @svanheule's new rtl8231 driver I guess to see if it will also keep the stock fan behaviour.

Support for RTL838x based managed switches

Shameless plug for my alternative RTL8231 driver: Owners of a GS1900 with RTL8380/82 SoC can just build the provided changes for their device. Other people wishing to test the new driver will have to modify their DTS according to the changes in gs1900.dtsi Happy testing!