add missing 'requests' field that zecke probably forgot to commit

diff --git a/include/openbsc/paging.h b/include/openbsc/paging.h
index 72b0f11..a04a906 100644
--- a/include/openbsc/paging.h
+++ b/include/openbsc/paging.h
@@ -36,6 +36,7 @@
 	struct llist_head entry;
 	struct gsm_subscriber *subscr;
 	struct gsm_bts *bts;
+	int requests;
 
 	int chan_type;
 };