Add 2-way path for SSSE3 version of ChaCha20
* cipher/chacha20-amd64-ssse3.S (_gcry_chacha20_amd64_ssse3_blocks1) (_gcry_chacha20_poly1305_amd64_ssse3_blocks1): Add 2-way code paths. * cipher/chacha20.c (_gcry_chacha20_poly1305_encrypt): Add preprosessing of 2 blocks with SSSE3.
- Signed-off-by: Jussi Kivilinna <jussi.kivilinna@iki.fi>