examples/default: add atmega256rfr2-xpro to board with netif
examples/default: add atmega256rfr2-xpro to board with netif

mtausig/RIOT,miri64/RIOT,authmillenon/RIOT,aeneby/RIOT,authmillenon/RIOT,yogo1212/RIOT,miri64/RIOT,josephnoir/RIOT,kYc0o/RIOT,basilfx/RIOT,kaspar030/RIOT,aeneby/RIOT,OTAkeys/RIOT,jasonatran/RIOT,OlegHahm/RIOT,aeneby/RIOT,smlng/RIOT,OTAkeys/RIOT,kYc0o/RIOT,RIOT-OS/RIOT,kaspar030/RIOT,authmillenon/RIOT,smlng/RIOT,yogo1212/RIOT,authmillenon/RIOT,RIOT-OS/RIOT,yogo1212/RIOT,x3ro/RIOT,toonst/RIOT,x3ro/RIOT,ant9000/RIOT,josephnoir/RIOT,kYc0o/RIOT,kYc0o/RIOT,kaspar030/RIOT,yogo1212/RIOT,OlegHahm/RIOT,miri64/RIOT,josephnoir/RIOT,miri64/RIOT,toonst/RIOT,yogo1212/RIOT,kaspar030/RIOT,ant9000/RIOT,smlng/RIOT,OlegHahm/RIOT,smlng/RIOT,jasonatran/RIOT,RIOT-OS/RIOT,x3ro/RIOT,RIOT-OS/RIOT,mtausig/RIOT,basilfx/RIOT,ant9000/RIOT,jasonatran/RIOT,kYc0o/RIOT,toonst/RIOT,ant9000/RIOT,basilfx/RIOT,OTAkeys/RIOT,x3ro/RIOT,OTAkeys/RIOT,toonst/RIOT,ant9000/RIOT,x3ro/RIOT,miri64/RIOT,aeneby/RIOT,toonst/RIOT,josephnoir/RIOT,OlegHahm/RIOT,basilfx/RIOT,smlng/RIOT,mtausig/RIOT,RIOT-OS/RIOT,jasonatran/RIOT,josephnoir/RIOT,authmillenon/RIOT,jasonatran/RIOT,kaspar030/RIOT,mtausig/RIOT,authmillenon/RIOT,OlegHahm/RIOT,OTAkeys/RIOT,yogo1212/RIOT,mtausig/RIOT,aeneby/RIOT,basilfx/RIOT