boards/arduino-mkrzero: Add board specific Kconfig symbols
boards/arduino-mkrzero: Add board specific Kconfig symbols

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