drivers: ieee802154_cc2520: fix unified build
drivers: ieee802154_cc2520: fix unified build

In the unified kernel legacy layer, both these functions are
implemented as #defines which can't be put in a struct.

Eventually this driver should be updated to use new APIs, but
this will get it to at least build which is the priority.

Change-Id: Ic5dfb5b85ff3bd0d1646f542340642549a2b2e05
Signed-off-by: Andrew Boie <aab045b28152628be6af0e556050d0381fd0a34d@intel.com>

bboozzoo/zephyr,fractalclone/zephyr-riscv,mbolivar/zephyr,mbolivar/zephyr,mbolivar/zephyr,kraj/zephyr,aceofall/zephyr-iotos,Vudentz/zephyr,sharronliu/zephyr,fbsder/zephyr,GiulianoFranchetto/zephyr,nashif/zephyr,GiulianoFranchetto/zephyr,fractalclone/zephyr-riscv,GiulianoFranchetto/zephyr,fbsder/zephyr,kraj/zephyr,galak/zephyr,tidyjiang8/zephyr-doc,runchip/zephyr-cc3220,Vudentz/zephyr,punitvara/zephyr,rsalveti/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,finikorg/zephyr,tidyjiang8/zephyr-doc,mbolivar/zephyr,explora26/zephyr,bboozzoo/zephyr,zephyriot/zephyr,pklazy/zephyr,kraj/zephyr,holtmann/zephyr,bigdinotech/zephyr,zephyriot/zephyr,runchip/zephyr-cc3200,aceofall/zephyr-iotos,bboozzoo/zephyr,erwango/zephyr,finikorg/zephyr,kraj/zephyr,bigdinotech/zephyr,explora26/zephyr,aceofall/zephyr-iotos,rsalveti/zephyr,runchip/zephyr-cc3220,erwango/zephyr,explora26/zephyr,holtmann/zephyr,ldts/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,runchip/zephyr-cc3220,fractalclone/zephyr-riscv,explora26/zephyr,galak/zephyr,holtmann/zephyr,punitvara/zephyr,bigdinotech/zephyr,mbolivar/zephyr,runchip/zephyr-cc3220,rsalveti/zephyr,sharronliu/zephyr,runchip/zephyr-cc3200,punitvara/zephyr,galak/zephyr,pklazy/zephyr,finikorg/zephyr,runchip/zephyr-cc3220,rsalveti/zephyr,zephyriot/zephyr,bboozzoo/zephyr,zephyriot/zephyr,nashif/zephyr,sharronliu/zephyr,holtmann/zephyr,explora26/zephyr,bboozzoo/zephyr,GiulianoFranchetto/zephyr,zephyrproject-rtos/zephyr,fbsder/zephyr,pklazy/zephyr,sharronliu/zephyr,bigdinotech/zephyr,ldts/zephyr,fractalclone/zephyr-riscv,aceofall/zephyr-iotos,erwango/zephyr,runchip/zephyr-cc3200,bigdinotech/zephyr,erwango/zephyr,fractalclone/zephyr-riscv,zephyrproject-rtos/zephyr,kraj/zephyr,pklazy/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,erwango/zephyr,fbsder/zephyr,ldts/zephyr,ldts/zephyr,Vudentz/zephyr,finikorg/zephyr,tidyjiang8/zephyr-doc,sharronliu/zephyr,runchip/zephyr-cc3200,punitvara/zephyr,punitvara/zephyr,nashif/zephyr,holtmann/zephyr,finikorg/zephyr,tidyjiang8/zephyr-doc,nashif/zephyr,zephyriot/zephyr,galak/zephyr,rsalveti/zephyr,GiulianoFranchetto/zephyr,runchip/zephyr-cc3200,Vudentz/zephyr,pklazy/zephyr,galak/zephyr,ldts/zephyr,tidyjiang8/zephyr-doc,aceofall/zephyr-iotos,fbsder/zephyr