netfilter: nf_tables: statify nft_expr_init()

Not exposed anymore to modules, statify this function.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h
index 52b872a..025ec14 100644
--- a/include/net/netfilter/nf_tables.h
+++ b/include/net/netfilter/nf_tables.h
@@ -846,8 +846,6 @@
 	return (void *)expr->data;
 }
 
-struct nft_expr *nft_expr_init(const struct nft_ctx *ctx,
-			       const struct nlattr *nla);
 void nft_expr_destroy(const struct nft_ctx *ctx, struct nft_expr *expr);
 int nft_expr_dump(struct sk_buff *skb, unsigned int attr,
 		  const struct nft_expr *expr);
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 1605a72..bc7a33f 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -2523,8 +2523,8 @@
 	module_put(type->owner);
 }
 
-struct nft_expr *nft_expr_init(const struct nft_ctx *ctx,
-			       const struct nlattr *nla)
+static struct nft_expr *nft_expr_init(const struct nft_ctx *ctx,
+				      const struct nlattr *nla)
 {
 	struct nft_expr_info info;
 	struct nft_expr *expr;