s390/zcrypt: Rework struct ap_qact_ap_info.

The ap_qact_ap_info struct can get more easy handled when the fields
in there can be accessed by their names but also the struct as a whole
with just an unsigned long value. This patch reworks this struct to be
a union and adapt the using code accordingly.

Signed-off-by: Harald Freudenberger <freude@linux.vnet.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>