netfilter: nf_flow_table: fix priv pointer for netdev hook

The offload ip hook expects a pointer to the flowtable, not to the
rhashtable. Since the rhashtable is the first member, this is safe for
the moment, but breaks as soon as the structure layout changes
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/nf_tables_api.c

@@ -5019,7 +5019,7 @@ static int nf_tables_flowtable_parse_hook(const struct nft_ctx *ctx,
 		flowtable->ops[i].pf		= NFPROTO_NETDEV;
 		flowtable->ops[i].hooknum	= hooknum;
 		flowtable->ops[i].priority	= priority;
-		flowtable->ops[i].priv		= &flowtable->data.rhashtable;
+		flowtable->ops[i].priv		= &flowtable->data;
 		flowtable->ops[i].hook		= flowtable->data.type->hook;
 		flowtable->ops[i].dev		= dev_array[i];
 		flowtable->dev_name[i]		= kstrdup(dev_array[i]->name,