PCUIF_Codec port, do not return fn in f_PCUIF_tx_imm_ass_pch

The function f_PCUIF_tx_imm_ass_pch() retuns the frame number, that is
sent back from osmo-bts via PCUIF / gsm_pcu_if_data_cnf_dt. Since we are
about to remove this field from gsm_pcu_if_data_cnf_dt, lets no longer
access it here as well. Also the return code is never used anywhere in
the tests. (In osmo-pcu the fn parameter was used for logging only, in
osmo-bts it was set to constant 0)

Related: OS#5927
Change-Id: I0e5bad7a0d74e5032f2818f6fdf5b9b2ecb531cc
diff --git a/bts/BTS_Tests.ttcn b/bts/BTS_Tests.ttcn
index e8ae1c0..ad6ae5a 100644
--- a/bts/BTS_Tests.ttcn
+++ b/bts/BTS_Tests.ttcn
@@ -5848,7 +5848,7 @@
 	f_l1_tune(L1CTL);
 
 	/* append 3 last imsi digits so BTS can compute pagng group */
-	var uint32_t fn := f_PCUIF_tx_imm_ass_pch(PCU, g_pcu_conn_id, imm_ass, '123459987'H);
+	f_PCUIF_tx_imm_ass_pch(PCU, g_pcu_conn_id, imm_ass, '123459987'H);
 
 	timer T := 0.5;
 	T.start;
diff --git a/library/PCUIF_CodecPort.ttcn b/library/PCUIF_CodecPort.ttcn
index 87a5b15..6d06ad4 100644
--- a/library/PCUIF_CodecPort.ttcn
+++ b/library/PCUIF_CodecPort.ttcn
@@ -140,7 +140,7 @@
 }
 
 function f_PCUIF_tx_imm_ass_pch(PCUIF_CODEC_PT pt, integer conn_id, octetstring imm_ass, hexstring imsi,
-				uint8_t bts_nr := 0, boolean wait_for_cnf := true, OCT4 msg_id := '01020304'O) return uint32_t {
+				uint8_t bts_nr := 0, boolean wait_for_cnf := true, OCT4 msg_id := '01020304'O) {
 	var PCUIF_send_data sd;
 	timer T := 3.0;
 
@@ -164,7 +164,7 @@
 
 	/* Exit early when the caller is not interested in the confirmation message */
 	if (wait_for_cnf == false) {
-		return 0;
+		return;
 	}
 
 	T.start;
@@ -175,7 +175,7 @@
 			mtc.stop;
 		} else {
 			log("IMM.ASS was sent on PCH at fn ", sd.data.u.data_cnf.fn);
-			return sd.data.u.data_cnf.fn;
+			return;
 		}
 		}
 	[] pt.receive(t_SD_PCUIF(conn_id, tr_PCUIF_DATA_CNF_DT(bts_nr, 0, 0, PCU_IF_SAPI_PCH_DT))) -> value sd {
@@ -183,8 +183,8 @@
 			setverdict(fail, "expecting tr_PCUIF_DATA_CNF in PCUIF v.10 or earlier");
 			mtc.stop;
 		} else {
-			log("IMM.ASS was sent on PCH at fn ", sd.data.u.data_cnf_dt.fn);
-			return sd.data.u.data_cnf_dt.fn;
+			log("IMM.ASS was sent on PCH");
+			return;
 		}
 		}
 	[] pt.receive { repeat; }
@@ -193,7 +193,6 @@
 		mtc.stop;
 		}
 	}
-	return 0;
 }