dav1d: Only return 0/1 from md5_verify
dav1d: Only return 0/1 from md5_verify

This makes the process exit codes more sensible when failing
verification; when there's a mismatch, memcmp returns the difference
between the two first differing bytes, which can fall outside of the
range of normal exit codes, into the range of exit codes used when
terminated by a signal.

videolan/dav1d