lantiq: improve DGN3500 LED definitions

lantiq: improve DGN3500 LED definitions

Add red:internet led on gpio 30 previously claimed as missing.
Wifi led was claimed as blue however there are no blue leds on the
board at all.  Actually there are two wifi leds, green & amber so add
definitions for those.  Make the newly discovered green wifi led gpio
14 the default.

There is no amber power led on this board. The mention of the amber
power led in the manual means power red and power green at the same
time.

Signed-off-by: Kevin Darbyshire-Bryant <kevin@darbyshire-bryant.me.uk>
[removed unnecessary aliases, add migration script]
Signed-off-by: Mathias Kresin <dev@kresin.me>