[GPRS] gb_proxy: Initiate RESET procedure on persistent NS-VC at startup

Some BSS that connect to the proxy do not continue to perform the
RESET procedure after a timeout.  In order to resurrect them, we
simply start a RESET procedure.
diff --git a/openbsc/src/gprs/gb_proxy.c b/openbsc/src/gprs/gb_proxy.c
index 5fbf9bf..1fe9e96 100644
--- a/openbsc/src/gprs/gb_proxy.c
+++ b/openbsc/src/gprs/gb_proxy.c
@@ -507,6 +507,18 @@
 	return rc;
 }
 
+int gbprox_reset_persistent_nsvcs(struct gprs_ns_inst *nsi)
+{
+	struct gprs_nsvc *nsvc;
+
+	llist_for_each_entry(nsvc, &nsi->gprs_nsvcs, list) {
+		if (!nsvc->persistent)
+			continue;
+		gprs_nsvc_reset(nsvc, NS_CAUSE_OM_INTERVENTION);
+	}
+	return 0;
+}
+
 /* Signal handler for signals from NS layer */
 int gbprox_signal(unsigned int subsys, unsigned int signal,
 		  void *handler_data, void *signal_data)