sgsn: Add user plane GTP testing (GTP->Gb and Gb->GTP)

Change-Id: Ifd62cca8cd9dbcffe4eac957db210ac13b8c633f
diff --git a/library/BSSGP_Emulation.ttcn b/library/BSSGP_Emulation.ttcn
index 9a48918..c4628be 100644
--- a/library/BSSGP_Emulation.ttcn
+++ b/library/BSSGP_Emulation.ttcn
@@ -702,6 +702,15 @@
 	sndcp := omit
 }
 
+template BssgpDecoded tr_BD_SNDCP(template BIT4 sapi, template PDU_SN sn) := {
+	bssgp := ?,
+	llc := tr_LLC_UI(?, sapi),
+	l3_mo := omit,
+	l3_mt := omit,
+	sndcp := sn
+}
+
+
 
 
 }