KVM: s390/cpacf: Enable/disable protected key functions for kvm guest

Created new KVM device attributes for indicating whether the AES and
DES/TDES protected key functions are available for programs running
on the KVM guest.  The attributes are used to set up the controls in
the guest SIE block that specify whether programs running on the
guest will be given access to the protected key functions available
on the s390 hardware.

Signed-off-by: Tony Krowiak <akrowiak@linux.vnet.ibm.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: Michael Mueller <mimu@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
[split MSA4/protected key into two patches]