vdpa: use first queue SVQ state for CVQ default

vdpa: use first queue SVQ state for CVQ default

Previous to this patch the only way CVQ would be shadowed is if it does
support to isolate CVQ group or if all vqs were shadowed from the
beginning.  The second condition was checked at the beginning, and no
more configuration was done.

After this series we need to check if data queues are shadowed because
they are in the middle of the migration.  As checking if they are
shadowed already covers the previous case, let's just mimic it.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20230822085330.3978829-2-eperezma@redhat.com>
Tested-by: Lei Yang <leiyang@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>