kconfig: make sync-deps flag accessible
kconfig: make sync-deps flag accessible

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