ath79: move label-mac-device out of dtsi

ath79: move label-mac-device out of dtsi

A script was ran that checks the label-mac-device node to see if it has
nvmem definitions as label-mac-device requires nvmem.

This is mostly a change to make the script happy. No indended functional
difference.

Add a change to qca9533_yuncore_cpe830.dts adding an nvmem definition to
wmac. Seems to have been some kind of oversight where it's specified in
nvmem but not used. label-mac-device needs an NVMEM definition.

Signed-off-by: Rosen Penev <rosenp@gmail.com>
Link: https://github.com/openwrt/openwrt/pull/22907
Signed-off-by: Robert Marko <robimarko@gmail.com>