sgsn: add TC_iu_attach_geran_rau

MS <-> SGSN: Attach over Iu
MS <-> SGSN: Routing Area Update over Geran

The tess case will crash the SGSN and is not included
in the default run.

Change-Id: Ie043639638a640a2041324fc910964385a41c77d
1 file changed