Enabling/disabling 4G RAN for given subscriber

The change adds support for enabling and disabling connection
through 4G RAN by a subscriber with use of USSD codes.

Change-Id: Idf964d9c770a0a1cb5c486eb2a7592d6bf44171c
diff --git a/src/luop.h b/src/luop.h
index 5a79722..51908b4 100644
--- a/src/luop.h
+++ b/src/luop.h
@@ -54,7 +54,7 @@
 	enum lu_state state;
 	/*! CS (false) or PS (true) Location Update? */
 	bool is_ps;
-	/*! RAT type indicator: coming in on GERAN-A? UTRAN-Iu? */
+	/*! RAT type indicator: coming in on GERAN-A? UTRAN-Iu? E-UTRAN?*/
 	enum osmo_rat_type via_rat;
 
 	/*! currently running timer */