MSC_Tests_Iu.ttcn: fix TC_iu_lu_and_mo_ussd_mo_release(): use proper BSC number

Change-Id: I58149f0e9cbae9684a8a899bfee81b0de609ccac
diff --git a/msc/MSC_Tests_Iu.ttcn b/msc/MSC_Tests_Iu.ttcn
index e592573..6491e27 100644
--- a/msc/MSC_Tests_Iu.ttcn
+++ b/msc/MSC_Tests_Iu.ttcn
@@ -383,7 +383,7 @@
 
 testcase TC_iu_lu_and_mo_ussd_mo_release() runs on MTC_CT {
 	var BSC_ConnHdlr vc_conn;
-	f_init();
+	f_init(3);
 	vc_conn := f_start_handler(refers(f_tc_lu_and_mo_ussd_mo_release), 1050, ran_idx := 2, ran_is_geran := false);
 	vc_conn.done;
 }