sha/asm/keccak1600-avx512.pl: improve performance by 17%.

Improvement is result of combination of data layout ideas from
Keccak Code Package and initial version of this module.

Hardware used for benchmarking courtesy of Atos, experiments run by
Romain Dolbeau <romain.dolbeau@atos.net>. Kudos!

Reviewed-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
Reviewed-by: Rich Salz <rsalz@openssl.org>