Hack: enable UL traffic in do-ra mode

This commit enables UL traffic in do-ra mode by doing two changes:
- configure SDAP to send traffic to TUN interface instead of GTP by
  abusing enb_flag=0 (i.e., setting UE mode for gNB SDAP)
- manually enable RLC LCID in UE MAC, since nr_DRB_preconfiguration()
  statically enables one DRB bearer, without notifying MAC

openair2/LAYER2/NR_MAC_UE/main_ue_nr.c

@@ -63,6 +63,7 @@ NR_UE_MAC_INST_t * nr_l2_init_ue(NR_UE_RRC_INST_t* rrc_inst) {
       if (IS_SOFTMODEM_NOS1){
         pdcp_layer_init();
         nr_DRB_preconfiguration(nr_ue_mac_inst->crnti);
+        nr_ue_mac_inst->logicalChannelBearer_exist[0] = true;
       }
       // Allocate memory for ul_config_request in the mac instance. This is now a pointer and will
       // point to a list of structures (one for each UL slot) to store PUSCH scheduling parameters

openair2/RRC/NR/rrc_gNB_nsa.c

@@ -374,6 +374,7 @@ void rrc_add_nsa_user(gNB_RRC_INST *rrc,struct rrc_gNB_ue_context_s *ue_context_
   }
 
   PROTOCOL_CTXT_SET_BY_MODULE_ID(&ctxt, rrc->module_id, GNB_FLAG_YES, ue_context_p->ue_id_rnti, 0, 0, rrc->module_id);
+  if (get_softmodem_params()->do_ra) ctxt.enb_flag = 0;
   LOG_W(RRC,
         "Calling RRC PDCP/RLC ASN1 request functions for protocol context %p with module_id %d, rnti %x, frame %d, subframe %d eNB_index %d \n",
         &ctxt,