Move FINISHED tbf_state transition to tbf_fsm

Related: OS#2709
Change-Id: I81f507e3a2821254f03364a58ead02333e63099f
diff --git a/src/tbf_dl.cpp b/src/tbf_dl.cpp
index 12fd99f..ed5003c 100644
--- a/src/tbf_dl.cpp
+++ b/src/tbf_dl.cpp
@@ -711,7 +711,7 @@
 				is_final = llc_queue_size(llc_queue()) == 0 && !keep_open(fn);
 				if (is_final) {
 					rdbi->cv = 0;
-					TBF_SET_STATE(this, TBF_ST_FINISHED);
+					osmo_fsm_inst_dispatch(this->state_fsm.fi, TBF_EV_LAST_DL_DATA_SENT, NULL);
 				}
 
 				if (mcs_is_edge(cs)) {
@@ -756,7 +756,7 @@
 
 		if (is_final) {
 			request_dl_ack();
-			TBF_SET_STATE(this, TBF_ST_FINISHED);
+			osmo_fsm_inst_dispatch(this->state_fsm.fi, TBF_EV_LAST_DL_DATA_SENT, NULL);
 		}
 
 		/* dequeue next LLC frame, if any */