realtek: skip SFP ports in PoE setup

realtek: skip SFP ports in PoE setup

The function `ucidef_set_poe` receives a list of ports to add to the PoE array.
Since switches have many ports the varibale `lan_list` is passed instead of
writing every single lan port. However, this list includes partly SFP ports
which are unrelated to PoE.

This commits adds the option to add a third parameter to manually exclide
interfaces, usually the last two.

Signed-off-by: Paul Spooren <mail@aparcar.org>