Some recent models of the Ubiquiti Networks UniFi 6 LR access point
come with a RealTek RTL8211FS 1000M/100M/10M PHY instead of the
Aquantia AQR112 2500M/1000M/100M/10M PHY used in both v1 and v2. Add
build for this variant so we can support Ethernet with the PHY.
Signed-off-by: Daniel Golle <daniel@makrotopia.org>