Remove file_type_subtype member from packet_info.

Just pass the necessary data to the frame dissector.

Change-Id: I1a4bab32f7b5e28f4e7707794d71b04dab388908
Reviewed-on: https://code.wireshark.org/review/5328
Reviewed-by: Michael Mann <mmann78@netscape.net>
Petri-Dish: Michael Mann <mmann78@netscape.net>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Alexis La Goutte <alexis.lagoutte@gmail.com>