rijndael/ppc: implement single-block mode, and implement OCB block cipher
* cipher/rijndael-ppc.c: New implementation of single-block mode, and implementation of OCB mode.
[jk: split rijndael-ppc.c from patch 'rijndael/ppc: reimplement
single-block mode, and implement OCB block cipher' for basis of new PowerPC vector crypto implementation of AES: https://lists.gnupg.org/pipermail/gcrypt-devel/2019-July/004765.html]
[jk: coding-style fixes]
- GnuPG-bug-id: T4529
- Signed-off-by: Jussi Kivilinna <jussi.kivilinna@iki.fi>