s390x assembly pack: update OPENSSL_s390xcap(3)
s390x assembly pack: update OPENSSL_s390xcap(3)

Add description of capability vector's pcc and kma parts.

Signed-off-by: Patrick Steuer <patrick.steuer@de.ibm.com>

Reviewed-by: Richard Levitte <5fb523282dd7956571c80524edc2dccfa0bd8234@openssl.org>
Reviewed-by: Shane Lontis <452ce16516ceed26291fe7de3f8b53540d83864e@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/9258)

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