cpu/atmega_common/gpio: use ARRAY_SIZE macro
cpu/atmega_common/gpio: use ARRAY_SIZE macro

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