ieee802154: Add NXP MCR20A IEEE 802.15.4 transceiver driver

The MCR20AVHM transceiver (or MCR20A) is a low power,
high-performance 2.4 GHz, IEEE 802.15.4 compliant transceiver.

This driver implements a subset of ieee802154_ops.
It has no support for CSMA due to lack of hardware support.
It has currently no support for its proprietary Dual-PAN feature.

https://www.nxp.com/docs/en/reference-manual/MCR20RM.pdf



Signed-off-by: Xue Liu <liuxuenetmail@gmail.com>
Signed-off-by: Stefan Schmidt <stefan@osg.samsung.com>