virtio-iommu: Consolidate host reserved regions and property set ones

virtio-iommu: Consolidate host reserved regions and property set ones

Up to now we were exposing to the RESV_MEM probe requests the
reserved memory regions set though the reserved-regions array property.

Combine those with the host reserved memory regions if any. Those
latter are tagged as RESERVED. We don't have more information about
them besides then cannot be mapped. Reserved regions set by
property have higher priority.

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: "Michael S. Tsirkin" <mst@redhat.com>
Tested-by: Yanghang Liu <yanghliu@redhat.com>
Signed-off-by: Cédric Le Goater <clg@redhat.com>