NSB TRex: convert DPDK port number to logical TRex port number

NSB TRex: convert DPDK port number to logical TRex port number

when we create TRex config we sort based on PCI bus address
and create a logical port ordering.

We need to save this port ordering and re-use it everywhere.

redirect vnfd_helper.port_num() to resource_helper.port_num() to
use the logical mapping

Change-Id: Ibff628556d5e11e686e15716a66a3210758c4ff0
Signed-off-by: Ross Brattain <ross.b.brattain@intel.com>