Fix a pair of aesthetic nits in dev/rnd.c:
Fix a pair of aesthetic nits in dev/rnd.c:

fix language (feed -> fed) in a comment
16 -> MD5_DIGEST_LENGTH for legibility

No change to resulting object file.

ok djm@

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