gprs_ns2: add gprs_ns2_fr_bind_role() to retrieve the fr role

Change-Id: I277b805e588ba68536789b4a64a428ea0b31728a
diff --git a/include/osmocom/gprs/gprs_ns2.h b/include/osmocom/gprs/gprs_ns2.h
index ef9a56a..0b3ea1f 100644
--- a/include/osmocom/gprs/gprs_ns2.h
+++ b/include/osmocom/gprs/gprs_ns2.h
@@ -182,6 +182,7 @@
 		struct gprs_ns2_inst *nsi,
 		const char *netif);
 const char *gprs_ns2_fr_bind_netif(struct gprs_ns2_vc_bind *bind);
+enum osmo_fr_role gprs_ns2_fr_bind_role(struct gprs_ns2_vc_bind *bind);
 int gprs_ns2_fr_bind(struct gprs_ns2_inst *nsi,
 		     const char *name,
 		     const char *netif,