This change append vnic-type vdpa to the list
of passthough vnic types and removes the api blocks
This should enable the existing suspend and live migrate
code to properly manage vdpa interfaces enabling
"hot plug" live migrations similar to direct sr-iov.
Implements: blueprint vdpa-suspend-detach-and-live-migrate
Change-Id: I878a9609ce0d84f7e3c2fef99e369b34d627a0df