tests/mtd_mapper: don't set device properites for regions
tests/mtd_mapper: don't set device properites for regions

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