BTS_Tests_LAPDm.TC_sabm_retransmit_bts: Fix time to wait

Wait 20 seconds, because T200 on SDCCH, SAPI 3 lasts about 2 seconds.

Relates: OS#5970
Change-Id: I593008420f58cc1d5e4778874f9071914d24f82e
diff --git a/bts/BTS_Tests_LAPDm.ttcn b/bts/BTS_Tests_LAPDm.ttcn
index 2e984d1..7dda8b8 100644
--- a/bts/BTS_Tests_LAPDm.ttcn
+++ b/bts/BTS_Tests_LAPDm.ttcn
@@ -287,7 +287,7 @@
 	LAPDM.clear;
 	RSL.send(ts_RSL_EST_REQ(g_chan_nr, ts_RslLinkID_DCCH(sapi)));
 
-	timer T := 8.0;
+	timer T := 20.0;
 	var integer sabm_received := 0;
 	T.start;
 	alt {
@@ -311,6 +311,7 @@
 }
 testcase TC_sabm_retransmit_bts() runs on test_CT {
 	var ConnHdlrPars pars := valueof(t_Pars(t_RslChanNr_Bm(1), ts_RSL_ChanMode_SIGN));
+	pars.t_guard := 30.0;
 	f_testmatrix_each_chan(pars, refers(f_TC_sabm_retransmit_bts));
 }