boards/common/nrf52: fix compilation of thingy52 and ruuvitag
boards/common/nrf52: fix compilation of thingy52 and ruuvitag

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