boards/common/saml1x: configure UART on EXT1
boards/common/saml1x: configure UART on EXT1

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