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/ggsn_tests/GGSN_Tests.default b/ggsn_tests/GGSN_Tests.default
index 33b96cb..9832ba1 100644
--- a/ggsn_tests/GGSN_Tests.default
+++ b/ggsn_tests/GGSN_Tests.default
@@ -21,6 +21,6 @@
 GGSN_Tests.m_ggsn_ip6_dns1 := "2001:4860:4860::8888"
 GGSN_Tests.m_ggsn_ip6_dns2 := "2001:4860:4860::8844"
 Osmocom_VTY_Functions.mp_prompt_prefix := "OsmoGGSN";
-GTP_CodecPort.mp_pl_SystemUnderTest := GGSN;
+GTPv1C_CodecPort.mp_pl_SystemUnderTest := GGSN;
 
 [EXECUTE]