netfilter: nf_tables: remove nhooks field from struct nft_af_info

We already validate the hook through bitmask, so this check is
superfluous. When removing this, this patch is also fixing a bug in the
new flowtable codebase, since ctx->afi points to the table family
instead of the netdev family which is where the flowtable is really
hooked in.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/bridge/netfilter/nf_tables_bridge.c

@@ -44,7 +44,6 @@ nft_do_chain_bridge(void *priv,
 
 static struct nft_af_info nft_af_bridge __read_mostly = {
 	.family		= NFPROTO_BRIDGE,
-	.nhooks		= NF_BR_NUMHOOKS,
 	.owner		= THIS_MODULE,
 };