KVM: s390: refactor crypto initialization

This patch refactors the code that initializes and sets up the
crypto configuration for a guest. The following changes are
implemented via this patch:

1. Introduces a flag indicating AP instructions executed on
   the guest shall be interpreted by the firmware. This flag
   is used to set a bit in the guest's state description
   indicating AP instructions are to be interpreted.

2. Replace code implementing AP interfaces with code supplied
   by the AP bus to query the AP configuration.

Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
Reviewed-by: Halil Pasic <pasic@linux.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Tested-by: Michael Mueller <mimu@linux.ibm.com>
Tested-by: Farhan Ali <alifm@linux.ibm.com>
Message-Id: <20180925231641.4954-4-akrowiak@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>