KVM: s390: add vector BCD enhancements facility to cpumodel

KVM: s390: add vector BCD enhancements facility to cpumodel

BugLink: https://bugs.launchpad.net/bugs/1836153
If vector support is enabled, the vector BCD enhancements facility
might also be enabled.
We can directly forward this facility to the guest if available
and VX is requested by user space.

Please note that user space can and will have the final decision
on the facility bits for a guests.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Collin Walling <walling@linux.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
(cherry picked from commit d5cb6ab1e3d4d7e0648a167f6290e89f6e86964e)
Signed-off-by: Frank Heimes <frank.heimes@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>