This makes it possible to use swconfig to controll the switch.
This was tested with devices using b43 and bgmac.
This was not tested on devices using tg3.
This does not support the adm switch used in some very old devices.
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@37304 3c298f89-4303-0410-b956-a3cf2f4a3e73