Speed up md5 hash filling/verifying by 20%

Get rid of the on-stack hash copies, hash directly into the buffer.
We need to 'fix' md5 to just initially clear a/b/c/d in md5_update().
Tested, works, generates same checksums.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
3 files changed