drivers: ieee802154: Add OpenThread modifications to KW41Z driver
drivers: ieee802154: Add OpenThread modifications to KW41Z driver

- Add modifications to the KW41Z driver to enable operation with
  OpenThread L2 layer.

Signed-off-by: David Leach <98707a1e43c521c5b5b81e36afef696dde6831a3@nxp.com>

zephyrproject-rtos/zephyr,punitvara/zephyr,mbolivar/zephyr,mbolivar/zephyr,punitvara/zephyr,finikorg/zephyr,galak/zephyr,punitvara/zephyr,mbolivar/zephyr,punitvara/zephyr,nashif/zephyr,zephyriot/zephyr,Vudentz/zephyr,explora26/zephyr,nashif/zephyr,ldts/zephyr,kraj/zephyr,kraj/zephyr,GiulianoFranchetto/zephyr,finikorg/zephyr,kraj/zephyr,Vudentz/zephyr,ldts/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,explora26/zephyr,galak/zephyr,Vudentz/zephyr,explora26/zephyr,ldts/zephyr,zephyrproject-rtos/zephyr,zephyriot/zephyr,explora26/zephyr,zephyrproject-rtos/zephyr,mbolivar/zephyr,Vudentz/zephyr,nashif/zephyr,GiulianoFranchetto/zephyr,galak/zephyr,GiulianoFranchetto/zephyr,kraj/zephyr,ldts/zephyr,punitvara/zephyr,galak/zephyr,Vudentz/zephyr,mbolivar/zephyr,ldts/zephyr,nashif/zephyr,finikorg/zephyr,Vudentz/zephyr,GiulianoFranchetto/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,zephyriot/zephyr,finikorg/zephyr,GiulianoFranchetto/zephyr,zephyriot/zephyr,kraj/zephyr,nashif/zephyr,explora26/zephyr,zephyriot/zephyr