sgsn: Introduce test TC_rim_eutran_to_geran

GTP_Templates.ttcn new templates use BssgpCellId, hence it depends on Osmocom_Gb_Types.ttcn.

Related: SYS#5314
Change-Id: I9dcf6ee2dc55bc6aba178eca30080233254f025e
diff --git a/sgsn/osmo-sgsn.cfg b/sgsn/osmo-sgsn.cfg
index 082a353..7941007 100644
--- a/sgsn/osmo-sgsn.cfg
+++ b/sgsn/osmo-sgsn.cfg
@@ -101,3 +101,6 @@
  timer t3397 8
  no compression rfc1144
  no compression v42bis
+ mme test-mme0
+  gtp remote-ip 127.0.0.103
+  gtp ran-info-relay 262 42 3