Make osmo_mgcpc_ep_fsm_pre_term() static

This is a call-back for FSM pre-termination and it should not
be publicly exported.

Change-Id: Iaa44906baa201571f6bc3192bd3caacb272fec0b
diff --git a/src/libosmo-mgcp-client/mgcp_client_endpoint_fsm.c b/src/libosmo-mgcp-client/mgcp_client_endpoint_fsm.c
index ea4c378..b8f09d5 100644
--- a/src/libosmo-mgcp-client/mgcp_client_endpoint_fsm.c
+++ b/src/libosmo-mgcp-client/mgcp_client_endpoint_fsm.c
@@ -997,7 +997,7 @@
 	return 0;
 }
 
-void osmo_mgcpc_ep_fsm_pre_term(struct osmo_fsm_inst *fi, enum osmo_fsm_term_cause cause)
+static void osmo_mgcpc_ep_fsm_pre_term(struct osmo_fsm_inst *fi, enum osmo_fsm_term_cause cause)
 {
 	int i;
 	struct osmo_mgcpc_ep *ep = osmo_mgcpc_ep_fi_mgwep(fi);