* cipher/camellia-aesni-avx-amd64.S
(_gcry_camellia_aesni_avx_ctr_enc): Add byte addition fast-path.
* cipher/camellia-aesni-avx2-amd64.h (ctr_enc): Likewise.
* cipher/camellia-gfni-avx512-amd64.S
(_gcry_camellia_gfni_avx512_ctr_enc): Likewise.
* cipher/camellia-glue.c (CAMELLIA_context): Add 'use_avx2'.
(camellia_setkey, _gcry_camellia_ctr_enc, _gcry_camellia_cbc_dec)
(_gcry_camellia_cfb_dec, _gcry_camellia_ocb_crypt)
(_gcry_camellia_ocb_auth) [USE_AESNI_AVX2]: Use 'use_avx2' to check
if any of the AVX2 implementations is enabled.