sgsn/test: Add GMM test for a GSUP based attach procedure

This test calls test_gmm_attach() where the mocked subscriber
functions insert GSUP messages instead of manipulating the
subscriber structure directly.

Sponsored-by: On-Waves ehf
diff --git a/openbsc/tests/sgsn/sgsn_test.ok b/openbsc/tests/sgsn/sgsn_test.ok
index b118328..a3c0342 100644
--- a/openbsc/tests/sgsn/sgsn_test.ok
+++ b/openbsc/tests/sgsn/sgsn_test.ok
@@ -11,6 +11,7 @@
 Auth policy 'remote': Testing GMM attach
 Auth policy 'remote', auth faked: Testing GMM attach
 Auth policy 'remote', triplet based auth: Testing GMM attach
+Auth policy 'remote', GSUP based auth: Testing GMM attach
 Testing GMM reject
   - Attach Request (invalid MI length)
   - Attach Request (invalid MI type)