move osmo_fsm_register() into constructor function

This way each application doesn't have to explicitly call it.

Change-Id: I20753d7f7f485e7e495b64fa74b24858cd22ffa9
diff --git a/src/remsim_client_fsm.c b/src/remsim_client_fsm.c
index 0776937..d361659 100644
--- a/src/remsim_client_fsm.c
+++ b/src/remsim_client_fsm.c
@@ -464,3 +464,9 @@
 	srvc_st_init_onenter(fi, 0);
 	return 0;
 }
+
+static __attribute__((constructor)) void on_dso_load(void)
+{
+	osmo_fsm_register(&remsim_client_bankd_fsm);
+	osmo_fsm_register(&remsim_client_server_fsm);
+}