s390x: Add hardware acceleration for full AES-XTS

s390x: Add hardware acceleration for full AES-XTS

The CPACF instruction KM provides support for accelerating the full
AES-XTS algorithm on newer machines for AES_XTS_128 and AES_XTS_256.

Preliminary measurements showed performance improvements of up to 50%,
dependent on the message size.

Signed-off-by: Holger Dengler <dengler@linux.ibm.com>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Paul Dale <pauli@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/25414)