Allow "cba" filter prefix for hf_ fields.  Seems like something with "pn" or (abbreviated) Profinet would make more sense (with dissectors to match), but trying to satisfy pre-commit check.

Change-Id: I1db5314fdc77ab7b909c955415f66f24da7d2a0a
Reviewed-on: https://code.wireshark.org/review/5838
Reviewed-by: Michael Mann <mmann78@netscape.net>