Revert: "ip6_tunnel: Update skb->protocol to ETH_P_IPV6 in ip6_tnl_xmit()"

This reverts commit ae148b08
("ip6_tunnel: Update skb->protocol to ETH_P_IPV6 in ip6_tnl_xmit()").

skb->protocol is now set in __ip_local_out() and __ip6_local_out() before
dst_output() is called. It is no longer necessary to do it for each tunnel.

Cc: stable@vger.kernel.org
Signed-off-by: Eli Cooper <elicooper@gmx.com>
Signed-off-by: David S. Miller <davem@davemloft.net>