netfilter: nf_tables: de-constify set commit ops function argument

The set backend using this already has to work around this via ugly
cast, don't spread this pattern.
Signed-off-by: Florian Westphal <fw@strlen.de>

include/net/netfilter/nf_tables.h

@@ -462,7 +462,7 @@ struct nft_set_ops {
 					       const struct nft_set *set,
 					       const struct nft_set_elem *elem,
 					       unsigned int flags);
-	void				(*commit)(const struct nft_set *set);
+	void				(*commit)(struct nft_set *set);
 	void				(*abort)(const struct nft_set *set);
 	u64				(*privsize)(const struct nlattr * const nla[],
 						    const struct nft_set_desc *desc);

net/netfilter/nft_set_pipapo.c

@@ -1549,12 +1549,11 @@ static void nft_pipapo_gc_deactivate(struct net *net, struct nft_set *set,
 
 /**
  * pipapo_gc() - Drop expired entries from set, destroy start and end elements
- * @_set:	nftables API set representation
+ * @set:	nftables API set representation
  * @m:		Matching data
  */
-static void pipapo_gc(const struct nft_set *_set, struct nft_pipapo_match *m)
+static void pipapo_gc(struct nft_set *set, struct nft_pipapo_match *m)
 {
-	struct nft_set *set = (struct nft_set *) _set;
 	struct nft_pipapo *priv = nft_set_priv(set);
 	struct net *net = read_pnet(&set->net);
 	int rules_f0, first_rule = 0;
@@ -1672,7 +1671,7 @@ static void pipapo_reclaim_match(struct rcu_head *rcu)
  * We also need to create a new working copy for subsequent insertions and
  * deletions.
  */
-static void nft_pipapo_commit(const struct nft_set *set)
+static void nft_pipapo_commit(struct nft_set *set)
 {
 	struct nft_pipapo *priv = nft_set_priv(set);
 	struct nft_pipapo_match *new_clone, *old;