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/libbsc/chan_alloc.c b/openbsc/src/libbsc/chan_alloc.c
index b794132..ff745f5 100644
--- a/openbsc/src/libbsc/chan_alloc.c
+++ b/openbsc/src/libbsc/chan_alloc.c
@@ -311,7 +311,7 @@
 
 
 	/* stop the timer */
-	bsc_del_timer(&lchan->T3101);
+	osmo_timer_del(&lchan->T3101);
 
 	/* clear cached measuement reports */
 	lchan->meas_rep_idx = 0;
@@ -356,9 +356,9 @@
  */
 void lchan_reset(struct gsm_lchan *lchan)
 {
-	bsc_del_timer(&lchan->T3101);
-	bsc_del_timer(&lchan->T3111);
-	bsc_del_timer(&lchan->error_timer);
+	osmo_timer_del(&lchan->T3101);
+	osmo_timer_del(&lchan->T3111);
+	osmo_timer_del(&lchan->error_timer);
 
 	lchan->type = GSM_LCHAN_NONE;
 	lchan->state = LCHAN_S_NONE;