netfilter: nft_payload: move struct nft_payload_set definition where it belongs

Not required to expose this header in nf_tables_core.h, move it to where
it is used, ie. nft_payload.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

include/net/netfilter/nf_tables_core.h

@@ -66,16 +66,6 @@ struct nft_payload {
 	u8			dreg;
 };
 
-struct nft_payload_set {
-	enum nft_payload_bases	base:8;
-	u8			offset;
-	u8			len;
-	u8			sreg;
-	u8			csum_type;
-	u8			csum_offset;
-	u8			csum_flags;
-};
-
 extern const struct nft_expr_ops nft_payload_fast_ops;
 
 extern const struct nft_expr_ops nft_bitwise_fast_ops;

net/netfilter/nft_payload.c

@@ -665,6 +665,16 @@ static int nft_payload_csum_inet(struct sk_buff *skb, const u32 *src,
 	return 0;
 }
 
+struct nft_payload_set {
+	enum nft_payload_bases	base:8;
+	u8			offset;
+	u8			len;
+	u8			sreg;
+	u8			csum_type;
+	u8			csum_offset;
+	u8			csum_flags;
+};
+
 static void nft_payload_set_eval(const struct nft_expr *expr,
 				 struct nft_regs *regs,
 				 const struct nft_pktinfo *pkt)