netfilter: nf_tables: remove unused variable

> Remove unused variable and fix missing initialization.
>
> >> net/netfilter/nf_tables_api.c:8266:6: warning: variable 'i' set but not used [-Wunused-but-set-variable]
>            int i;
>                ^

Fixes: 2c865a8a ("netfilter: nf_tables: add rule blob layout")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/nf_tables_api.c

@@ -8264,14 +8264,12 @@ static int nf_tables_commit_chain_prepare(struct net *net, struct nft_chain *cha
 	void *data, *data_boundary;
 	struct nft_rule_dp *prule;
 	struct nft_rule *rule;
-	int i;
 
 	/* already handled or inactive chain? */
 	if (chain->blob_next || !nft_is_active_next(net, chain))
 		return 0;
 
 	rule = list_entry(&chain->rules, struct nft_rule, list);
-	i = 0;
 
 	data_size = 0;
 	list_for_each_entry_continue(rule, &chain->rules, list) {