drivers/nrf802154: add missing __cpluscplus closing bracket
drivers/nrf802154: add missing __cpluscplus closing bracket

kYc0o/RIOT,OlegHahm/RIOT,authmillenon/RIOT,jasonatran/RIOT,RIOT-OS/RIOT,kaspar030/RIOT,kYc0o/RIOT,jasonatran/RIOT,authmillenon/RIOT,ant9000/RIOT,kaspar030/RIOT,authmillenon/RIOT,authmillenon/RIOT,OlegHahm/RIOT,miri64/RIOT,kYc0o/RIOT,ant9000/RIOT,ant9000/RIOT,miri64/RIOT,OlegHahm/RIOT,RIOT-OS/RIOT,jasonatran/RIOT,miri64/RIOT,authmillenon/RIOT,miri64/RIOT,RIOT-OS/RIOT,kYc0o/RIOT,OlegHahm/RIOT,ant9000/RIOT,jasonatran/RIOT,kaspar030/RIOT,RIOT-OS/RIOT,jasonatran/RIOT,miri64/RIOT,kaspar030/RIOT,kYc0o/RIOT,authmillenon/RIOT,kaspar030/RIOT,ant9000/RIOT,OlegHahm/RIOT,RIOT-OS/RIOT