[NETFILTER]: x_tables: fix xt_register_table error propagation

When xt_register_table fails the error is not properly propagated back.
Based on patch by Lepton Wu <ytht.net@gmail.com>.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv4/netfilter/arp_tables.c

@@ -1120,7 +1120,8 @@ int arpt_register_table(struct arpt_table *table,
 		return ret;
 	}
 
-	if (xt_register_table(table, &bootstrap, newinfo) != 0) {
+	ret = xt_register_table(table, &bootstrap, newinfo);
+	if (ret != 0) {
 		xt_free_table_info(newinfo);
 		return ret;
 	}

net/ipv4/netfilter/ip_tables.c

@@ -2113,7 +2113,8 @@ int ipt_register_table(struct xt_table *table, const struct ipt_replace *repl)
 		return ret;
 	}
 
-	if (xt_register_table(table, &bootstrap, newinfo) != 0) {
+	ret = xt_register_table(table, &bootstrap, newinfo);
+	if (ret != 0) {
 		xt_free_table_info(newinfo);
 		return ret;
 	}

net/ipv6/netfilter/ip6_tables.c

@@ -1281,7 +1281,8 @@ int ip6t_register_table(struct xt_table *table,
 		return ret;
 	}
 
-	if (xt_register_table(table, &bootstrap, newinfo) != 0) {
+	ret = xt_register_table(table, &bootstrap, newinfo);
+	if (ret != 0) {
 		xt_free_table_info(newinfo);
 		return ret;
 	}