ns2: add support for frame relay

Add support for frame relay over dahdi hdlc device.
It's supporting lmi by q933 and supports both
SGSN and BSS.

Change-Id: Id3b49f93d33c271f77cd9c9db03cde6b727a4d30
diff --git a/src/gb/gprs_ns2_internal.h b/src/gb/gprs_ns2_internal.h
index 493b391..6ea2fcc 100644
--- a/src/gb/gprs_ns2_internal.h
+++ b/src/gb/gprs_ns2_internal.h
@@ -60,6 +60,7 @@
 enum gprs_ns_ll {
 	GPRS_NS_LL_UDP,		/*!< NS/UDP/IP */
 	GPRS_NS_LL_E1,		/*!< NS/E1 */
+	GPRS_NS_LL_FR,		/*!< NS/FR */
 	GPRS_NS_LL_FR_GRE,	/*!< NS/FR/GRE/IP */
 };