Cleanup unused and/or long time commented out code in RRC/NGAP

* Remove drb_is_active: function is unused and the logic will be later
  added to another function to add DRBs if necessary
* Remove unused NGAP structs and empty TODO functions
* Remove unused pdusession_setup_req_t struct definition

openair3/NGAP/ngap_gNB.c

@@ -344,14 +344,6 @@ void *ngap_gNB_process_itti_msg(void *notUsed) {
         ngap_gNB_nas_non_delivery_ind(instance, &NGAP_NAS_NON_DELIVERY_IND(received_msg));
         break;
 
-      case NGAP_PATH_SWITCH_REQ:
-        ngap_gNB_path_switch_req(instance, &NGAP_PATH_SWITCH_REQ(received_msg));
-        break;
-
-      case NGAP_PDUSESSION_MODIFICATION_IND:
-        ngap_gNB_generate_PDUSESSION_Modification_Indication(instance, &NGAP_PDUSESSION_MODIFICATION_IND(received_msg));
-        break;
-
       case NGAP_UE_CONTEXT_RELEASE_COMPLETE:
         ngap_ue_context_release_complete(instance, &NGAP_UE_CONTEXT_RELEASE_COMPLETE(received_msg));
         break;

openair3/NGAP/ngap_gNB_nas_procedures.c

@@ -1225,17 +1225,3 @@ int ngap_gNB_pdusession_release_resp(instance_t instance, ngap_pdusession_releas
   return 0;
 }
 
-int ngap_gNB_path_switch_req(instance_t instance, ngap_path_switch_req_t *path_switch_req_p)
-//------------------------------------------------------------------------------
-{
-  //TODO
-
-  return 0;
-}
-
-int ngap_gNB_generate_PDUSESSION_Modification_Indication(instance_t instance, ngap_pdusession_modification_ind_t *pdusession_modification_ind)
-//-----------------------------------------------------------------------------
-{
-  //TODO
-  return 0;
-}

openair3/NGAP/ngap_gNB_nas_procedures.h

@@ -63,10 +63,4 @@ int ngap_gNB_pdusession_modify_resp(instance_t instance,
 int ngap_gNB_pdusession_release_resp(instance_t instance,
                                 ngap_pdusession_release_resp_t *pdusession_release_resp_p);
 
-int ngap_gNB_path_switch_req(instance_t instance,
-                             ngap_path_switch_req_t *path_switch_req_p);
-
-int ngap_gNB_generate_PDUSESSION_Modification_Indication(
-		instance_t instance, ngap_pdusession_modification_ind_t *pdusession_modification_ind);
-
 #endif /* NGAP_GNB_NAS_PROCEDURES_H_ */