KVM: s390: vsie: Allow CRYCB FORMAT-2

When the guest and the host both use CRYCB FORMAT-2,
we copy the guest's FORMAT-1 APCB to a FORMAT-1
shadow APCB.

This patch also cleans up the shadow_crycb() function.

Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
Message-Id: <20180925231641.4954-19-akrowiak@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>