NBAP: fix ddi missed for non first macdflow_id in E-DCH channel

Change-Id: Ib93cac8a4b186114f50ef4a26bdace2d72219644
Reviewed-on: https://code.wireshark.org/review/6022
Petri-Dish: Alexis La Goutte <alexis.lagoutte@gmail.com>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Alexis La Goutte <alexis.lagoutte@gmail.com>
Reviewed-by: Michael Mann <mmann78@netscape.net>