NTB: ntb_test: Add ntb_tool port tests

Multi-port interface is now available in ntb_tool driver. According
to the new NTB API, there might be more than two devices connected over
NTB. It means each device can have multiple freely enumerated ports.
Each port got index assigned by NTB hardware driver. This test is
performed to determine the local and peer ports as well as their indexes.

Signed-off-by: Serge Semin <fancer.lancer@gmail.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>