Fix a couple more missing "static" markers.

contrib/pg_upgrade/check.c

@@ -452,7 +452,7 @@ create_script_for_old_cluster_deletion(
  *	by value.  The schema dumps the CREATE TYPE PASSEDBYVALUE setting so
  *	it must match for the old and new servers.
  */
-void
+static void
 check_for_isn_and_int8_passing_mismatch(ClusterInfo *cluster)
 {
 	int			dbnum;
@@ -546,7 +546,7 @@ check_for_isn_and_int8_passing_mismatch(ClusterInfo *cluster)
  *	not preserved, and hence these data types cannot be used in user
  *	tables upgraded by pg_upgrade.
  */
-void
+static void
 check_for_reg_data_type_usage(ClusterInfo *cluster)
 {
 	int			dbnum;