netfilter: fix ptr_ret.cocci warnings

net/netfilter/nft_numgen.c:117:1-3: WARNING: PTR_ERR_OR_ZERO can be used
net/netfilter/nft_hash.c:180:1-3: WARNING: PTR_ERR_OR_ZERO can be used
net/netfilter/nft_hash.c:223:1-3: WARNING: PTR_ERR_OR_ZERO can be used

 Use PTR_ERR_OR_ZERO rather than if(IS_ERR(...)) + PTR_ERR

Generated by: scripts/coccinelle/api/ptr_ret.cocci

Fixes: b9ccc07e ("netfilter: nft_hash: add map lookups for hashing operations")
Fixes: d734a288 ("netfilter: nft_numgen: add map lookups for numgen statements")
CC: Laura Garcia Liebana <nevola@gmail.com>
Signed-off-by: kbuild test robot <fengguang.wu@intel.com>
Acked-by: Laura Garcia Liebana <nevola@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/nft_hash.c

@@ -177,10 +177,7 @@ static int nft_jhash_map_init(const struct nft_ctx *ctx,
 	priv->map = nft_set_lookup_global(ctx->net, ctx->table,
 					  tb[NFTA_HASH_SET_NAME],
 					  tb[NFTA_HASH_SET_ID], genmask);
-	if (IS_ERR(priv->map))
-		return PTR_ERR(priv->map);
-
-	return 0;
+	return PTR_ERR_OR_ZERO(priv->map);
 }
 
 static int nft_symhash_init(const struct nft_ctx *ctx,
@@ -220,10 +217,7 @@ static int nft_symhash_map_init(const struct nft_ctx *ctx,
 	priv->map = nft_set_lookup_global(ctx->net, ctx->table,
 					  tb[NFTA_HASH_SET_NAME],
 					  tb[NFTA_HASH_SET_ID], genmask);
-	if (IS_ERR(priv->map))
-		return PTR_ERR(priv->map);
-
-	return 0;
+	return PTR_ERR_OR_ZERO(priv->map);
 }
 
 static int nft_jhash_dump(struct sk_buff *skb,

net/netfilter/nft_numgen.c

@@ -114,10 +114,7 @@ static int nft_ng_inc_map_init(const struct nft_ctx *ctx,
 					  tb[NFTA_NG_SET_NAME],
 					  tb[NFTA_NG_SET_ID], genmask);
 
-	if (IS_ERR(priv->map))
-		return PTR_ERR(priv->map);
-
-	return 0;
+	return PTR_ERR_OR_ZERO(priv->map);
 }
 
 static int nft_ng_dump(struct sk_buff *skb, enum nft_registers dreg,