netfilter: nf_tables: kill nft_validate_output_register()

All users of nft_validate_register_store() first invoke
nft_validate_output_register(). There is in fact no use for using it
on its own, so simplify the code by folding the functionality into
nft_validate_register_store() and kill it.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
diff --git a/net/netfilter/nft_byteorder.c b/net/netfilter/nft_byteorder.c
index 03bfb75..848bce0 100644
--- a/net/netfilter/nft_byteorder.c
+++ b/net/netfilter/nft_byteorder.c
@@ -115,15 +115,8 @@
 		return err;
 
 	priv->dreg = ntohl(nla_get_be32(tb[NFTA_BYTEORDER_DREG]));
-	err = nft_validate_output_register(priv->dreg);
-	if (err < 0)
-		return err;
-	err = nft_validate_register_store(ctx, priv->dreg, NULL,
-					  NFT_DATA_VALUE, priv->len);
-	if (err < 0)
-		return err;
-
-	return 0;
+	return nft_validate_register_store(ctx, priv->dreg, NULL,
+					   NFT_DATA_VALUE, priv->len);
 }
 
 static int nft_byteorder_dump(struct sk_buff *skb, const struct nft_expr *expr)