o do not break after first iteration but when we found a match. o try to read the whole cis (but not more than len bytes) instead of the   first 256 bytes.
o do not break after first iteration but when we found a match.
o try to read the whole cis (but not more than len bytes) instead of the
  first 256 bytes.

first one spotted by lint.  mickey@, krw@ and deraadt@ ok.

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