s390/zcrypt: Rework cca findcard() implementation and callers

Rework the memory usage of the cca findcard() implementation:
- findcard does not allocate memory for the list of apqns
  any more.
- the callers are now responsible to provide an array of
  apqns to store the matching apqns into.

Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Reviewed-by: Holger Dengler <dengler@linux.ibm.com>
Link: https://lore.kernel.org/r/20250424133619.16495-14-freude@linux.ibm.com


Signed-off-by: Heiko Carstens <hca@linux.ibm.com>