BSC_Tests: fix TC_assignment_osmux_cn: use c_mr_conf_5_90

Currently this testcase fails:

  RSL MR CONFIG IE does not match expectation.
  Expected: { other := { len := 2, payload := '2804'O } }

Change-Id: Icc5381eccb924803b1117b46d2b4c47cee6dabd7
diff --git a/bsc/BSC_Tests.ttcn b/bsc/BSC_Tests.ttcn
index f6f8c9c..cd9514e 100644
--- a/bsc/BSC_Tests.ttcn
+++ b/bsc/BSC_Tests.ttcn
@@ -5251,18 +5251,10 @@
 	var TestHdlrParams pars := f_gen_test_hdlr_pars();
 	var MSC_ConnHdlr vc_conn;
 
-	/* See note above */
-	var RSL_IE_Body mr_conf := {
-		other := {
-			len := 2,
-			payload := '2804'O
-		}
-	};
-
 	pars.ass_codec_list := valueof(ts_BSSMAP_IE_CodecList({ts_CodecAMR_H}));
 	pars.ass_codec_list.codecElements[0].s0_7 := '00000100'B; /* 5,90k */
 	pars.ass_codec_list.codecElements[0].s8_15 := '00000111'B;
-	pars.expect_mr_conf_ie := mr_conf;
+	pars.expect_mr_conf_ie := c_mr_conf_5_90;
 	pars.use_osmux_cn := true;
 
 	g_osmux_enabled_cn := true;