Use Devicetree to describe the radio and IEEE 802.15.4. This allows to
remove usage of IEEE802154_KW41Z_DRV_NAME in preparation for the removal
of NET_CONFIG_IEEE802154_DEV_NAME.
KW41Z files have been updated with the addition of radio and an
ieee802154 nodes The peripheral has been enabled in the frdm_k41z board
(used for testing ieee802154).
Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>
Gerard Marull-Paretas