GSM_Types: Switch TLLI from uint32_t to OCT4

The TLLI is not really a number, but an opaque 4-byte value.

Change-Id: I0901340a2211eeeb899f312bcc60573fec11f220
diff --git a/gprs_gb/Test.ttcn b/gprs_gb/Test.ttcn
index e9cb40e..7251ef9 100644
--- a/gprs_gb/Test.ttcn
+++ b/gprs_gb/Test.ttcn
@@ -47,7 +47,7 @@
 		var BSSGP_CT bssgp_component;
 
 		var MmContext g_mmctx := {
-			tlli := 0,
+			tlli := 'FFFFFFFF'O,
 			n_u := 0
 		};
 
@@ -334,7 +334,7 @@
 
 	/* compute a random TLLI; FIXME: what about TLLI prefix / local/foreign/...? */
 	function f_random_tlli() return GprsTlli {
-		var GprsTlli tlli := float2int(rnd()* 4294967295.0);
+		var GprsTlli tlli := f_rnd_octstring(4);
 		return tlli;
 	}
 
@@ -402,7 +402,7 @@
 				[] BSSGP.receive(tr_BD_BSSGP(?)) -> value bd {
 					log("BSSGP Rx: ", bd);
 					//log("GMM Rx: ", dec_PDU_L3_MS_SGSN(pdu.payload));
-					g_mmctx.tlli := oct2int(bd.bssgp.pDU_BSSGP_UL_UNITDATA.tLLI);
+					g_mmctx.tlli := bd.bssgp.pDU_BSSGP_UL_UNITDATA.tLLI;
 					tx_gmm(LLC_CR_DL_CMD, gmm_auth_req);
 				}
 				[] BSSGP.receive(t_BssgpStsInd(?, ?, BVC_S_UNBLOCKED)) { repeat; }