s390/zcrypt: Fix memory leak with CCA cards used as accelerator

Tests showed that there is a memory leak if CCA cards are used as
accelerator for clear key RSA requests (ME and CRT). With the last
rework for the memory allocation the AP messages are allocated by
ap_init_apmsg() but for some reason on two places (ME and CRT) the
older allocation was still in place. So the first allocation simple
was never freed.

Fixes: 57db62a130ce ("s390/ap/zcrypt: Rework AP message buffer allocation")
Reported-by: Yi Zhang <yi.zhang@redhat.com>
Closes: https://lore.kernel.org/linux-s390/CAHj4cs9H67Uz0iVaRQv447p7JFPRPy3TKAT4=Y6_e=wSHCZM5w@mail.gmail.com/
Reported-by: Nadja Hariz <Nadia.Hariz@ibm.com>
Cc: stable@vger.kernel.org
Reviewed-by: Ingo Franzki <ifranzki@linux.ibm.com>
Reviewed-by: Holger Dengler <dengler@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>