Eliminate proto_tree_add_text from packet-tds.c

Change-Id: Ib3dc7f8a87e55ef34d4847f4837d645e418607a3
Reviewed-on: https://code.wireshark.org/review/4826
Petri-Dish: Michael Mann <mmann78@netscape.net>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Michael Mann <mmann78@netscape.net>