drivers/ethos: avoid explicit cast to netdev
drivers/ethos: avoid explicit cast to netdev

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