6lowpan: set 6lowpan network and transport header

This is necessary to access network header with the skb_network_header
function instead of calculate the position with mac_len, etc.
Do the same for the transport header, when we replace the IPv6 header
with the 6LoWPAN header.
Signed-off-by: NAlexander Aring <alex.aring@gmail.com>
Acked-by: NWerner Almesberger <werner@almesberger.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ieee802154/6lowpan.c

@@ -654,7 +654,9 @@ static int lowpan_header_create(struct sk_buff *skb,
 	head[1] = iphc1;
 
 	skb_pull(skb, sizeof(struct ipv6hdr));
+	skb_reset_transport_header(skb);
 	memcpy(skb_push(skb, hc06_ptr - head), head, hc06_ptr - head);
+	skb_reset_network_header(skb);
 
 	lowpan_raw_dump_table(__func__, "raw skb data dump", skb->data,
 				skb->len);