ipv6: Don't reset inner headers in ip6_tnl_xmit

Since iptunnel_handle_offloads() is called in all paths we can
probably drop the block in ip6_tnl_xmit that was checking for
skb->encapsulation and resetting the inner headers.
Signed-off-by: NTom Herbert <tom@herbertland.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv6/ip6_tunnel.c

@@ -1120,11 +1120,6 @@ int ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev, __u8 dsfield,
 		ipv6_push_nfrag_opts(skb, &opt.ops, &proto, NULL);
 	}
 
-	if (likely(!skb->encapsulation)) {
-		skb_reset_inner_headers(skb);
-		skb->encapsulation = 1;
-	}
-
 	/* Calculate max headroom for all the headers and adjust
 	 * needed_headroom if necessary.
 	 */