hmac: Allow use of shorter salt.
* cipher/md.c (prepare_macpads): Move the check to... * src/visibility.c (gcry_mac_setkey): ... here.
Cherry-picking the master commit of:
58c92098d053aae7c78cc42bdd7c80c13efc89bb
- GnuPG-bug-id: T6039
- Fixes-commit: 76aad97dd312e83f2f9b8d086553f2b72ab6546f
- Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>