Split GTP_CodecPort/GTP_Templates into C and U variants

The Types are already split in the dependent modules in GTPC_Types and
GTPU_Types.
There's no point in keeping them together in the same file since those 2
protocols are mostly independent.
Furthermore, testsuites using GTPv2C + GTPv1U don't need GTPv1C.

Change-Id: Ic15c9a2e92828cbafb4dda7355ee534107051e2d
diff --git a/hnodeb/HNB_Tests.ttcn b/hnodeb/HNB_Tests.ttcn
index df7a04c..1178695 100644
--- a/hnodeb/HNB_Tests.ttcn
+++ b/hnodeb/HNB_Tests.ttcn
@@ -53,7 +53,7 @@
 import from HNBLLIF_Templates all;
 
 import from GTPU_Types all;
-import from GTP_Templates all;
+import from GTPv1U_Templates all;
 import from GTP_Emulation all;
 
 import from IuUP_Types all;