sha/asm/keccak1600-s390x.pl: typo and readability, minor size optimization.
sha/asm/keccak1600-s390x.pl: typo and readability, minor size optimization.

Reviewed-by: Bernd Edlinger <ac6902843ae77cc0d49b9c8ddec4cbf141db1bb7@hotmail.de>

openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl