netfilter: nft_inner: fix return value check in nft_inner_parse_l2l3()

In nft_inner_parse_l2l3(), the return value of skb_header_pointer() is
'veth' instead of 'eth' when case 'htons(ETH_P_8021Q)' and fix it.

Fixes: 3a07327d ("netfilter: nft_inner: support for inner tunnel header matching")
Signed-off-by: Peng Wu <wupeng58@huawei.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/nft_inner.c

@@ -72,7 +72,7 @@ static int nft_inner_parse_l2l3(const struct nft_inner *priv,
 			break;
 		case htons(ETH_P_8021Q):
 			veth = skb_header_pointer(pkt->skb, off, sizeof(_veth), &_veth);
-			if (!eth)
+			if (!veth)
 				return -1;
 
 			outer_llproto = veth->h_vlan_encapsulated_proto;