We are currently missing the deallocation of the [host_]resv_regions
in case of hot unplug. Also to make things more simple let's rule
out the case where multiple HostIOMMUDevices would be aliased and
attached to the same IOMMUDevice. This allows to remove the handling
of conflicting Host reserved regions. Anyway this is not properly
supported at guest kernel level. On hotunplug the reserved regions
are reset to the ones set by virtio-iommu property.
Signed-off-by: Eric Auger <eric.auger@redhat.com>