KVM: s390: vsie: Do not shadow CRYCB when no AP and no keys

When the guest do not have AP instructions nor Key management
we should return without shadowing the CRYCB.

We did not check correctly in the past.

Fixes: b10bd9a2 ("s390: vsie: Use effective CRYCBD.31 to check CRYCBD validity")
Fixes: 6ee74098 ("KVM: s390: vsie: allow CRYCB FORMAT-0")

Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
Reported-by: Christian Borntraeger <borntraeger@de.ibm.com>
Message-Id: <1556269010-22258-1-git-send-email-pmorel@linux.ibm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Tested-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>