sha3-avx512: fix for "x32" target
* cipher/keccak.c (_gcry_keccak_absorb_blocks_avx512): Change size_t to u64; change 'const byte **new_lanes' to 'u64 *new_lanes'. (keccak_absorb_lanes64_avx512): Get new lines pointer from assembly through 'u64' type.
- Signed-off-by: Jussi Kivilinna <jussi.kivilinna@iki.fi>