[packet-cp2179.c] - Added support for Function Code 0x04 and perform misc...

[packet-cp2179.c] - Added support for Function Code 0x04 and perform misc comment & variable-name clean-ups

Change-Id: I484eb9986e144f43b5e170717c582756f0e3404f
Reviewed-on: https://code.wireshark.org/review/29453


Petri-Dish: Anders Broman <a.broman58@gmail.com>
Tested-by: Petri Dish Buildbot
Reviewed-by: Anders Broman <a.broman58@gmail.com>