bssgp_bvc_fsm: check return value of osmo_fsm_register()

Change-Id: I0ade2e476a035bb44b2f135ece4552d015852274
Fixes: CID#215717
diff --git a/src/gb/bssgp_bvc_fsm.c b/src/gb/bssgp_bvc_fsm.c
index 6de0028..6b8bd14 100644
--- a/src/gb/bssgp_bvc_fsm.c
+++ b/src/gb/bssgp_bvc_fsm.c
@@ -819,5 +819,5 @@
 
 static __attribute__((constructor)) void on_dso_load_bvc_fsm(void)
 {
-	osmo_fsm_register(&bssgp_bvc_fsm);
+	OSMO_ASSERT(osmo_fsm_register(&bssgp_bvc_fsm) == 0);
 }