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/libcommon/gsup_client.c b/openbsc/src/libcommon/gsup_client.c
index 2e920a6..de00d8d 100644
--- a/openbsc/src/libcommon/gsup_client.c
+++ b/openbsc/src/libcommon/gsup_client.c
@@ -254,8 +254,7 @@
 
 static void start_test_procedure(struct gsup_client *gsupc)
 {
-	gsupc->ping_timer.data = gsupc;
-	gsupc->ping_timer.cb = &ping_timer_cb;
+	osmo_timer_setup(&gsupc->ping_timer, ping_timer_cb, gsupc);
 
 	gsupc->got_ipa_pong = 0;
 	osmo_timer_schedule(&gsupc->ping_timer, GSUP_CLIENT_PING_INTERVAL, 0);
@@ -290,8 +289,7 @@
 	if (!gsupc->link)
 		goto failed;
 
-	gsupc->connect_timer.data = gsupc;
-	gsupc->connect_timer.cb = &connect_timer_cb;
+	osmo_timer_setup(&gsupc->connect_timer, connect_timer_cb, gsupc);
 
 	rc = gsup_client_connect(gsupc);