Use snprintf() to simplify device name construction, removing now superfluous variables and the function 'number()'.
Use snprintf() to simplify device name construction, removing now
superfluous variables and the function 'number()'.

ok deraadt@ and millert@

orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars