mvebu: simplify etc/board.d/02_network

Unify switch configuration on Linksys WRTxx00AC series.
LAN = eth0, WAN = eth1

Signed-off-by: Paul Wassi <p.wassi@gmx.at>
[Álvaro]: also change WAN LEDs
Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>