ipvlan: Make skb->skb_iif track skb->dev for l3s mode

For l3s mode, skb->dev is set to ipvlan interface in ipvlan_nf_input():
  skb->dev = addr->master->dev
but, skb->skb_iif remain unchanged, this will cause socket lookup failed
if a target socket is bound to a interface, like the following example:

  ip link add ipvlan0 link eth0 type ipvlan mode l3s
  ip addr add dev ipvlan0 192.168.124.111/24
  ip link set ipvlan0 up

  ping -c 1 -I ipvlan0 8.8.8.8
  100% packet loss

This is because there is no match sk in __raw_v4_lookup() as sk->sk_bound_dev_if != dif(skb->skb_iif).
Fix this by make skb->skb_iif track skb->dev in ipvlan_nf_input().

Fixes: c675e06 ("ipvlan: decouple l3s mode dependencies from other modes")
Signed-off-by: Jianguo Wu <wujianguo@chinatelecom.cn>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Link: https://lore.kernel.org/r/29865b1f-6db7-c07a-de89-949d3721ea30@163.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ipvlan/ipvlan_l3s.c

@@ -101,6 +101,7 @@ static unsigned int ipvlan_nf_input(void *priv, struct sk_buff *skb,
 		goto out;
 
 	skb->dev = addr->master->dev;
+	skb->skb_iif = skb->dev->ifindex;
 	len = skb->len + ETH_HLEN;
 	ipvlan_count_rx(addr->master, len, true, false);
 out: