Shuffle calculation of physical block so that bounds checking is not off by 48 blocks (metadata + metdata offset).  Found by drahn. Fix panic message while in the same area.
Shuffle calculation of physical block so that bounds checking is not off by
48 blocks (metadata + metdata offset).  Found by drahn.
Fix panic message while in the same area.

Help from otto who wrote a diff that worked around the issue.

ok deraadt

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