Improve mapping function for 1n-skx vpp_device to pickup
available DUT1 net_dev and replace the name with TG net_dev prefix.
This way we can eliminate situation, when pair with not equal VLANs
are picked.
Change-Id: If78329e730bfb4df34fb8d8924c8715d69a15e0c Signed-off-by: Peter Mikus <pmikus@cisco.com>