cosmetic: subscr_conn_fsm_auth_ciph() should be static

Only used in subscr_conn.c.

Change-Id: Iaa2c63d2b06f59d34e0465c40a98741f56ec526a
diff --git a/src/libmsc/subscr_conn.c b/src/libmsc/subscr_conn.c
index 78af274..a63297f 100644
--- a/src/libmsc/subscr_conn.c
+++ b/src/libmsc/subscr_conn.c
@@ -136,7 +136,7 @@
 	}
 }
 
-void subscr_conn_fsm_auth_ciph(struct osmo_fsm_inst *fi, uint32_t event, void *data)
+static void subscr_conn_fsm_auth_ciph(struct osmo_fsm_inst *fi, uint32_t event, void *data)
 {
 	/* If accepted, transition the state, all other cases mean failure. */
 	switch (event) {