netfilter: nf_tables: kill nft_data_cmp()

Only needlessly complicates things due to requiring specific argument
types. Use memcmp directly.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
diff --git a/net/netfilter/nft_cmp.c b/net/netfilter/nft_cmp.c
index 59391e6..b7e1c58 100644
--- a/net/netfilter/nft_cmp.c
+++ b/net/netfilter/nft_cmp.c
@@ -31,7 +31,7 @@
 	const struct nft_cmp_expr *priv = nft_expr_priv(expr);
 	int d;
 
-	d = nft_data_cmp(&regs->data[priv->sreg], &priv->data, priv->len);
+	d = memcmp(&regs->data[priv->sreg], &priv->data, priv->len);
 	switch (priv->op) {
 	case NFT_CMP_EQ:
 		if (d != 0)