netfilter: nf_tables_offload: skip EBUSY on chain update

Do not try to bind a chain again if it exists, otherwise the driver
returns EBUSY.

Fixes: c9626a2c ("netfilter: nf_tables: add hardware offload support")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/nf_tables_offload.c

@@ -334,7 +334,8 @@ int nft_flow_rule_offload_commit(struct net *net)
 
 		switch (trans->msg_type) {
 		case NFT_MSG_NEWCHAIN:
-			if (!(trans->ctx.chain->flags & NFT_CHAIN_HW_OFFLOAD))
+			if (!(trans->ctx.chain->flags & NFT_CHAIN_HW_OFFLOAD) ||
+			    nft_trans_chain_update(trans))
 				continue;
 
 			policy = nft_trans_chain_policy(trans);