trau_sync: Check return value of osmo_fsm_register()

Change-Id: Ieaf524423033864a8b79ea1b04b62568d10ffbd3
Closes: CID#211593
diff --git a/src/trau/trau_sync.c b/src/trau/trau_sync.c
index dfd7ce4..730cf0c 100644
--- a/src/trau/trau_sync.c
+++ b/src/trau/trau_sync.c
@@ -524,5 +524,5 @@
 
 	for (i = 0; i < ARRAY_SIZE(sync_patterns); i++)
 		sync_pattern_register(&sync_patterns[i]);
-	osmo_fsm_register(&trau_sync_fsm);
+	OSMO_ASSERT(osmo_fsm_register(&trau_sync_fsm) == 0);
 }