s390/zcrypt: Support CPRB minor version T7

There is a new CPRB minor version T7 to be supported with
this patch. Together with this the functions which extract
the CPRB data from userspace and prepare the AP message do
now check the CPRB minor version and provide some info in
the flag field of the ap message struct for further processing.

The 3 functions doing this job have been renamed to
prep_cca_ap_msg, prep_ep11_ap_msg and prep_rng_ap_msg to
reflect their job better (old was get..fc).

This patch also introduces two new flags to be used internal
with the flag field of the struct ap_message:

AP_MSG_FLAG_USAGE is set when prep_cca_ap_msg or prep_ep11_ap_msg
come to the conclusion that this is a ordinary crypto load CPRB
(which means T2 for CCA CPRBs and no admin bit for EP11 CPRBs).

AP_MSG_FLAG_ADMIN is set when prep_cca_ap_msg or prep_ep11_ap_msg
think, this is an administrative (control) crypto load CPRB
(which means T3, T5, T6 or T7 for CCA CPRBs and admin bit set
for EP11 CPRBs).

Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Reviewed-by: Jürgen Christ <jchrist@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>