boards/arduino-zero: update PWM configuration
boards/arduino-zero: update PWM configuration

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