NTB: ntb_test: Update ntb_perf tests

ntb_perf driver has been also updated so to have the multi-port
interface support. User now must specify what peer port is going
to be used to perform the test.

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