sys/net/netopt: minor style fixes
sys/net/netopt: minor style fixes

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