lantiq: use the device tree bindings from rt2x00 driver

Set a device specific wireless mac address for ARV7506PW11, VGV7519 and
VGV7510KW22. The one from the EEPROM is a generic one and the same on
all boards.

Use the wifi@0,0 label and the pci0,0 compatible string for the
ARV7519PW and ARV7525PW since the pci vendor and device id is unknown.
It should work anyway since the compatible string isn't evaluated
(yet).

Signed-off-by: Mathias Kresin <dev@kresin.me>