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/bsc_rll.c b/openbsc/src/libbsc/bsc_rll.c
index b02394a..9fbe7c6 100644
--- a/openbsc/src/libbsc/bsc_rll.c
+++ b/openbsc/src/libbsc/bsc_rll.c
@@ -34,7 +34,7 @@
 
 struct bsc_rll_req {
 	struct llist_head list;
-	struct timer_list timer;
+	struct osmo_timer_list timer;
 
 	struct gsm_lchan *lchan;
 	uint8_t link_id;
@@ -92,7 +92,7 @@
 	rllr->timer.cb = &timer_cb;
 	rllr->timer.data = rllr;
 
-	bsc_schedule_timer(&rllr->timer, 10, 0);
+	osmo_timer_schedule(&rllr->timer, 10, 0);
 
 	/* send the RSL RLL ESTablish REQuest */
 	return rsl_establish_request(rllr->lchan, rllr->link_id);
@@ -107,7 +107,7 @@
 	llist_for_each_entry_safe(rllr, rllr2, &bsc_rll_reqs, list) {
 		if (rllr->lchan == lchan &&
 		    (rllr->link_id & LINKID_MASK) == (link_id & LINKID_MASK)) {
-			bsc_del_timer(&rllr->timer);
+			osmo_timer_del(&rllr->timer);
 			complete_rllr(rllr, type);
 			return;
 		}
@@ -127,7 +127,7 @@
 
 	llist_for_each_entry_safe(rllr, rllr2, &bsc_rll_reqs, list) {
 		if (rllr->lchan == challoc->lchan) {
-			bsc_del_timer(&rllr->timer);
+			osmo_timer_del(&rllr->timer);
 			complete_rllr(rllr, BSC_RLLR_IND_ERR_IND);
 		}
 	}