paging: Go through all BTS to stop paging

As the comment says we should not rely that the paging
occurs on the current LAC. We might page at more BTS.
Walk all the BTS to stop paging. No callbacks will be
issued by this stop operation.
diff --git a/openbsc/src/libbsc/paging.c b/openbsc/src/libbsc/paging.c
index 6b46c6d..9ae28e0 100644
--- a/openbsc/src/libbsc/paging.c
+++ b/openbsc/src/libbsc/paging.c
@@ -391,28 +391,21 @@
 			 struct gsm_subscriber_connection *conn,
 			 struct msgb *msg)
 {
-	struct gsm_bts *bts = NULL;
+	struct gsm_bts *bts;
 
 	log_set_context(BSC_CTX_SUBSCR, subscr);
 
+	/* Stop this first and dispatch the request */
 	if (_bts)
 		_paging_request_stop(_bts, subscr, conn, msg);
 
-	do {
-		/*
-		 * FIXME: Don't use the lac of the subscriber...
-		 * as it might have magically changed the lac.. use the
-		 * location area of the _bts as reconfiguration of the
-		 * network is probably happening less often.
-		 */
-		bts = gsm_bts_by_lac(subscr->group->net, subscr->lac, bts);
-		if (!bts)
-			break;
-
-		/* Stop paging */
-		if (bts != _bts)
-			_paging_request_stop(bts, subscr, NULL, NULL);
-	} while (1);
+	/* Make sure to cancel this everywhere else */
+	llist_for_each_entry(bts, &subscr->group->net->bts_list, list) {
+		/* Sort of an optimization. */
+		if (bts == _bts)
+			continue;
+		_paging_request_stop(bts, subscr, NULL, NULL);
+	}
 }
 
 void paging_update_buffer_space(struct gsm_bts *bts, uint16_t free_slots)