This patch removes the hdr variable (which is copied into the skb)
and instead sets the header directly in the skb.

It also uses __skb_push instead of skb_push since we've just checked
using skb_cow for enough head room.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>