TODO - remove dependency on ifconfig

[Stephen Hemminger]

It would be good if DTS and DPDK docs and test did not use the ifconfig command.
Ifconfig is not maintained and is deprecated. Some distros have stopped shipping it.
Ifconfig only used ioctl's and was never updated to handle the many kinds of interfaces
and devices in Linux.

The documentation part is relatively straight forward, but there are lots
of calls to ifconfig in DTS.