boards/common/saml1x: Add Kconfig symbols
boards/common/saml1x: Add Kconfig symbols

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