sched, bpf: let stack handle !IFF_UP devs on bpf_clone_redirect

Similarly as already the case in bpf_redirect()/skb_do_redirect()
pair, let the stack deal with devs that are !IFF_UP.

dev_forward_skb() as well as dev_queue_xmit() will free the skb
and increment drop counter internally in such cases, so we can
spare the condition in bpf_clone_redirect().
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NAlexei Starovoitov <ast@plumgrid.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/core/filter.c

@@ -1404,9 +1404,6 @@ static u64 bpf_clone_redirect(u64 r1, u64 ifindex, u64 flags, u64 r4, u64 r5)
 	if (unlikely(!dev))
 		return -EINVAL;
 
-	if (unlikely(!(dev->flags & IFF_UP)))
-		return -EINVAL;
-
 	skb2 = skb_clone(skb, GFP_ATOMIC);
 	if (unlikely(!skb2))
 		return -ENOMEM;