s390/zcrypt: Fix ap_max_domain_id for older machine types

According to the system architecture the current implementation
requires the presence of the N bit in GR2 in the TAPQ response
field to validate the max. number of domains (Nd).
Older machine types don't have this N bit, hence the max. domain
field was ignored.

Before the N bit was introduced the maximum number of domain was
a constant value of 15. So set this value in case of N bit absence.
Signed-off-by: Ingo Tuchscherer <ingo.tuchscherer@linux.vnet.ibm.com>
Signed-off-by: Harald Freudenberger <freude@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

drivers/s390/crypto/ap_bus.c

@@ -271,8 +271,11 @@ static int ap_query_queue(ap_qid_t qid, int *queue_depth, int *device_type,
 		*facilities = (unsigned int)(info >> 32);
 		/* Update maximum domain id */
 		nd = (info >> 16) & 0xff;
+		/* if N bit is available, z13 and newer */
 		if ((info & (1UL << 57)) && nd > 0)
 			ap_max_domain_id = nd;
+		else /* older machine types */
+			ap_max_domain_id = 15;
 		switch (*device_type) {
 			/* For CEX2 and CEX3 the available functions
 			 * are not refrected by the facilities bits.