vDPA/ifcvf: get_vendor_id returns a device specific vendor id

In this commit, ifcvf_get_vendor_id() will return
a device specific vendor id of the probed pci device
than a hard code.

Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Link: https://lore.kernel.org/r/20210317094933.16417-2-lingshan.zhu@intel.com


Signed-off-by: Michael S. Tsirkin <mst@redhat.com>