don't match on L1CTL SAPI in received frames

L1 has no idea about the SAPI encoded in LAPDm when it passes a
PH-DATA.ind up to us.  So dont match on that L1CTL field, only match the
SAPI we decoded from LAPDm header.
diff --git a/lapd/L1CTL_Test.ttcn b/lapd/L1CTL_Test.ttcn
index e3d149e..acd19cc 100644
--- a/lapd/L1CTL_Test.ttcn
+++ b/lapd/L1CTL_Test.ttcn
@@ -89,10 +89,10 @@
 		log("====> expecting ", t_PH_DATA(sapi, use_sacch, LAPDm_B_UA(sapi, payload)));
 		T.start
 		alt {
-			[] LAPDM.receive(t_PH_DATA(sapi, use_sacch, LAPDm_B_UA(sapi, payload))) { result := true; }
-			[] LAPDM.receive(t_PH_DATA(sapi, use_sacch, ?)) -> value phd { log("Other msg on DCH: ", phd); repeat; }
+			[] LAPDM.receive(t_PH_DATA(?, use_sacch, LAPDm_B_UA(sapi, payload))) { result := true; }
+			[] LAPDM.receive(t_PH_DATA(?, use_sacch, ?)) -> value phd { log("Other msg on DCH: ", phd); repeat; }
 			[] LAPDM.receive(t_PH_DATA(?, ?, ?)) -> value phd { log("Other PH-DATA: ", phd); repeat; }
-			[] T.timeout { setverdict(fail); }
+			[] T.timeout { }
 		}
 		f_release_dcch();
 		return result;
@@ -108,24 +108,24 @@
 
 	testcase TC_sabm_ua_dcch_sapi0_nopayload() runs on dummy_CT {
 		f_init();
-		if (not f_test_sabm_results_in_ua(0, false, ''O)) {
-			setverdict(fail);
+		if (f_test_sabm_results_in_ua(0, false, ''O)) {
+			setverdict(fail, "Initial SABM/UA must contain L3 payload but BTS accepts without");
 		}
 		setverdict(pass);
 	}
 
 	testcase TC_sabm_ua_dcch_sapi3() runs on dummy_CT {
 		f_init();
-		if (not f_test_sabm_results_in_ua(3, false, 'FEFE'O)) {
-			setverdict(fail);
+		if (f_test_sabm_results_in_ua(3, false, 'FEFE'O)) {
+			setverdict(fail, "Initial SABM/UA must be on SAPI0, but BTS accepts SAPI=3");
 		}
 		setverdict(pass);
 	}
 
 	testcase TC_sabm_ua_dcch_sapi4() runs on dummy_CT {
 		f_init();
-		if (not f_test_sabm_results_in_ua(4, false, 'FEFE'O)) {
-			setverdict(fail);
+		if (f_test_sabm_results_in_ua(4, false, 'FEFE'O)) {
+			setverdict(fail, "Initial SABM/UA must be on SAPI0, but BTS accepts SAPI=4");
 		}
 		setverdict(pass);
 	}