fix warning: parameter 'list' not found in the function declaration [-Wdocumentation]

Change-Id: Id6d02f5c1383dd8f231707f519ec1b28fb007079
Reviewed-on: https://code.wireshark.org/review/5978
Reviewed-by: Evan Huus <eapache@gmail.com>

epan/packet.h

@@ -359,7 +359,6 @@ typedef struct {
  *  Call this in the parent dissectors proto_register function.
  *
  * @param name the name of this protocol
- * @param list the list of heuristic sub-dissectors to be registered
  */
 WS_DLL_PUBLIC heur_dissector_list_t register_heur_dissector_list(const char *name);