hv_netvsc: ignore devices that are not PCI

Registering another device with same MAC address (such as TAP, VPN or
DPDK KNI) will confuse the VF autobinding logic.  Restrict the search
to only run if the device is known to be a PCI attached VF.

Fixes: e8ff40d4

 ("hv_netvsc: improve VF device matching")
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>