src: use namespace prefix osmo_timer* for timer functions

Summary of changes:

s/struct timer_list/struct osmo_timer_list/g
s/bsc_add_timer/osmo_timer_add/g
s/bsc_schedule_timer/osmo_timer_schedule/g
s/bsc_del_timer/osmo_timer_del/g
s/bsc_timer_pending/osmo_timer_pending/g
s/bsc_nearest_timer/osmo_timers_nearest/g
s/bsc_prepare_timers/osmo_timers_prepare/g
s/bsc_update_timers/osmo_timers_update/g
s/bsc_timer_check/osmo_timers_check/g
diff --git a/openbsc/src/gprs/gprs_sndcp.h b/openbsc/src/gprs/gprs_sndcp.h
index ec35d7b..fef871a 100644
--- a/openbsc/src/gprs/gprs_sndcp.h
+++ b/openbsc/src/gprs/gprs_sndcp.h
@@ -20,7 +20,7 @@
 	/* linked list of defrag_queue_entry: one for each fragment  */
 	struct llist_head frag_list;
 
-	struct timer_list timer;
+	struct osmo_timer_list timer;
 };
 
 /* See 6.7.1.2 Reassembly */