fabrics: add default port number for NVMe/TCP I/O controllers

fabrics: add default port number for NVMe/TCP I/O controllers

As per section 7.4.9.3 "Transport Service Identifier" of the NVMe over
Fabrics 1.1 specification, the default IANA port number for a NVMe/TCP
discovery controller is 8009. But at the same time, it also clearly
states that NVMe/TCP I/O controllers should not use TCP port number
8009, but may instead use 4420 as the default here.

So make sure to fill these values appropriately, and pass it down.

Signed-off-by: Martin George <marting@netapp.com>