src: use osmo_timer_setup()

Use new function available in libosmocore to set up timers. Compile
tested only.

Change-Id: Ibcfd915688e97d370a888888a83a7c95cbe16819
diff --git a/openbsc/src/libbsc/bsc_rll.c b/openbsc/src/libbsc/bsc_rll.c
index f2b65ca..bb488da 100644
--- a/openbsc/src/libbsc/bsc_rll.c
+++ b/openbsc/src/libbsc/bsc_rll.c
@@ -89,9 +89,7 @@
 
 	llist_add(&rllr->list, &bsc_rll_reqs);
 
-	rllr->timer.cb = &timer_cb;
-	rllr->timer.data = rllr;
-
+	osmo_timer_setup(&rllr->timer, timer_cb, rllr);
 	osmo_timer_schedule(&rllr->timer, 7, 0);
 
 	/* send the RSL RLL ESTablish REQuest */