Using DPDK in Hyper-V VM systems requires vdev_netvsc driver to pair
the NetVSC netdev device with the same MAC address PCI device by
fail-safe PMD.
Add vdev_netvsc custom scan in vdev bus to allow automatic probing in
Hyper-V VM systems unless it was already specified by command line.
Add "ignore" parameter to disable this auto-detection.
Signed-off-by: Matan Azrad <matan@mellanox.com>