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/libabis/input/dahdi.c b/openbsc/src/libabis/input/dahdi.c
index 93c8fa5..4fcd64f 100644
--- a/openbsc/src/libabis/input/dahdi.c
+++ b/openbsc/src/libabis/input/dahdi.c
@@ -222,7 +222,7 @@
 	/* set tx delay timer for next event */
 	e1i_ts->sign.tx_timer.cb = timeout_ts1_write;
 	e1i_ts->sign.tx_timer.data = e1i_ts;
-	bsc_schedule_timer(&e1i_ts->sign.tx_timer, 0, 50000);
+	osmo_timer_schedule(&e1i_ts->sign.tx_timer, 0, 50000);
 
 	return 0;
 }