cip: Access FT_UINT16 hf_cip_sc_create_instance with proper encoding-arg.

Specifically: Use ENC_LITTLE_ENDIAN (not ENC_NA) to match all
              other integral fetches in the cip dissector.

Change-Id: I5d330084168493f53135dbb97674a2dba9ed7477
Reviewed-on: https://code.wireshark.org/review/5732
Reviewed-by: Bill Meier <wmeier@newsguy.com>
Reviewed-by: Michael Mann <mmann78@netscape.net>