vDPA/ifcvf: deduce VIRTIO device ID from pdev ids

This commit deduces the VIRTIO device ID of a probed
device from its pdev device ids.

Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
Link: https://lore.kernel.org/r/20210317094933.16417-8-lingshan.zhu@intel.com


Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>