KVM: s390: use facilities and cpu_id per KVM

The patch introduces facilities and cpu_ids per virtual machine.
Different virtual machines may want to expose different facilities and
cpu ids to the guest, so let's make them per-vm instead of global.

Signed-off-by: Michael Mueller <mimu@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>