s390x assembly pack: remove capability double-checking.

An instruction's QUERY function is executed at initialization, iff the required
MSA level is installed. Therefore, it is sufficient to check the bits returned
by the QUERY functions. The MSA level does not have to be checked at every
function call.
crypto/aes/asm/aes-s390x.pl: The AES key schedule must be computed if the
required KM or KMC function codes are not available. Formally, the availability
of a KMC function code does not imply the availability of the corresponding KM
function code.

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

Reviewed-by: Andy Polyakov <appro@openssl.org>
Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/4501)