sniffer: Avoid relying on printf support for 64 bit numbers
sniffer: Avoid relying on printf support for 64 bit numbers

kaspar030/RIOT,jasonatran/RIOT,miri64/RIOT,ant9000/RIOT,ant9000/RIOT,jasonatran/RIOT,ant9000/RIOT,RIOT-OS/RIOT,miri64/RIOT,RIOT-OS/RIOT,kaspar030/RIOT,kaspar030/RIOT,ant9000/RIOT,RIOT-OS/RIOT,miri64/RIOT,ant9000/RIOT,RIOT-OS/RIOT,jasonatran/RIOT,jasonatran/RIOT,kaspar030/RIOT,RIOT-OS/RIOT,miri64/RIOT,kaspar030/RIOT,jasonatran/RIOT,miri64/RIOT