Use nvmem framework for supported mac-address stored
in nvmem cells and drop mac patch function for hotplug
script for supported devices.
Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
[rebase, move to correct node for d7800, include xr500]
Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>