bridge: move mac header copying into br_netfilter

The mac header only has to be copied back into the skb for
fragments generated by ip_fragment(), which only happens
for bridge forwarded packets with nf-call-iptables=1 && active nf_defrag.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
diff --git a/net/bridge/br_forward.c b/net/bridge/br_forward.c
index f96933a..32541d4 100644
--- a/net/bridge/br_forward.c
+++ b/net/bridge/br_forward.c
@@ -37,9 +37,7 @@
 
 int br_dev_queue_push_xmit(struct sk_buff *skb)
 {
-	/* ip_fragment doesn't copy the MAC header */
-	if (nf_bridge_maybe_copy_header(skb) ||
-	    !is_skb_forwardable(skb->dev, skb)) {
+	if (!is_skb_forwardable(skb->dev, skb)) {
 		kfree_skb(skb);
 	} else {
 		skb_push(skb, ETH_HLEN);