[SK_BUFF]: Some more simple skb_reset_network_header conversions

This time of the type:

 skb->nh.iph = (struct iphdr *)skb->data;

That is completely equivalent to:

 skb->nh.raw = skb->data;

Wonder why people love casts... :-)

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>