[paging] Cleanup page -> paging in function names

diff --git a/include/openbsc/gsm_data.h b/include/openbsc/gsm_data.h
index b96ec40..c87b25d 100644
--- a/include/openbsc/gsm_data.h
+++ b/include/openbsc/gsm_data.h
@@ -205,7 +205,7 @@
 	struct gsm_bts *bts;
 
 	/* tick timer */
-	struct timer_list page_timer;
+	struct timer_list paging_timer;
 };
 
 /* One BTS */