RSL_Emulation: Make CCHAN_PT bi-directional

So far we only dispatched received Common Channel messages from the
wire / IUT into the CCHAN_PT. Now the tester can also send Common
Channel messages back to the wire / IUT.

Change-Id: If3d5516c14ea3fbbd8c3de35eaa8ea5f18a00933
diff --git a/library/RSL_Emulation.ttcn b/library/RSL_Emulation.ttcn
index bf6686a..635ee42 100644
--- a/library/RSL_Emulation.ttcn
+++ b/library/RSL_Emulation.ttcn
@@ -396,6 +396,10 @@
 			IPA_PT.send(ts_ASP_RSL_UD(ConnectionTable[cid].stream_id, rx_rsl_msg));
 			}
 
+		[] CCHAN_PT.receive(tr_RSL(?)) -> value rx_rsl {
+			IPA_PT.send(ts_ASP_RSL_UD(rx_rsl.streamId, rx_rsl.rsl));
+			}
+
 		/* explicit registration, e.g. in (non-immediate) assignment case */
 		[] RSL_PROC.getcall(RSLEM_register:{?,?,?}) -> param(trx_nr, chan_nr, vc_conn) {
 			f_cid_create_cnr(trx_nr, chan_nr, vc_conn);