netstats_l2: remove obsolete struct from netdev_t
netstats_l2: remove obsolete struct from netdev_t

ant9000/RIOT,kYc0o/RIOT,RIOT-OS/RIOT,miri64/RIOT,BytesGalore/RIOT,kYc0o/RIOT,miri64/RIOT,ant9000/RIOT,authmillenon/RIOT,basilfx/RIOT,A-Paul/RIOT,yogo1212/RIOT,miri64/RIOT,kYc0o/RIOT,miri64/RIOT,cladmi/RIOT,kYc0o/RIOT,yogo1212/RIOT,kYc0o/RIOT,x3ro/RIOT,mtausig/RIOT,OTAkeys/RIOT,OTAkeys/RIOT,cladmi/RIOT,RIOT-OS/RIOT,kaspar030/RIOT,mfrey/RIOT,OTAkeys/RIOT,mtausig/RIOT,OlegHahm/RIOT,A-Paul/RIOT,BytesGalore/RIOT,RIOT-OS/RIOT,mfrey/RIOT,kaspar030/RIOT,kaspar030/RIOT,OlegHahm/RIOT,kaspar030/RIOT,mtausig/RIOT,OTAkeys/RIOT,mtausig/RIOT,josephnoir/RIOT,RIOT-OS/RIOT,jasonatran/RIOT,lazytech-org/RIOT,aeneby/RIOT,x3ro/RIOT,josephnoir/RIOT,authmillenon/RIOT,authmillenon/RIOT,lazytech-org/RIOT,cladmi/RIOT,jasonatran/RIOT,josephnoir/RIOT,ant9000/RIOT,aeneby/RIOT,A-Paul/RIOT,OlegHahm/RIOT,x3ro/RIOT,miri64/RIOT,smlng/RIOT,BytesGalore/RIOT,OlegHahm/RIOT,lazytech-org/RIOT,yogo1212/RIOT,ant9000/RIOT,BytesGalore/RIOT,aeneby/RIOT,smlng/RIOT,BytesGalore/RIOT,OlegHahm/RIOT,basilfx/RIOT,toonst/RIOT,toonst/RIOT,A-Paul/RIOT,ant9000/RIOT,x3ro/RIOT,lazytech-org/RIOT,basilfx/RIOT,OTAkeys/RIOT,rfuentess/RIOT,mfrey/RIOT,rfuentess/RIOT,smlng/RIOT,jasonatran/RIOT,authmillenon/RIOT,toonst/RIOT,RIOT-OS/RIOT,josephnoir/RIOT,mtausig/RIOT,mfrey/RIOT,rfuentess/RIOT,toonst/RIOT,aeneby/RIOT,kaspar030/RIOT,jasonatran/RIOT,basilfx/RIOT,yogo1212/RIOT,yogo1212/RIOT,toonst/RIOT,rfuentess/RIOT,cladmi/RIOT,smlng/RIOT,yogo1212/RIOT,authmillenon/RIOT,x3ro/RIOT,A-Paul/RIOT,smlng/RIOT,lazytech-org/RIOT,aeneby/RIOT,josephnoir/RIOT,basilfx/RIOT,mfrey/RIOT,authmillenon/RIOT,cladmi/RIOT,jasonatran/RIOT,rfuentess/RIOT