Revert "kernel: backport export ipv6_push_frag_opts for tunneling now"

This reverts commit daa73b63d5.
The fix has already been imported by
commit b7735d8113 ("kernel: import follow-up fix for previous backport").
The patch won't apply twice.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>

target/linux/generic/backport-4.9/094-v4.12-0002-ipv6-Need-to-export-ipv6_push_frag_opts-for-tunnelin.patch

@@ -1,31 +0,0 @@
-From 5b8481fa42ac58484d633b558579e302aead64c1 Mon Sep 17 00:00:00 2001
-From: "David S. Miller" <davem@davemloft.net>
-Date: Mon, 1 May 2017 15:10:20 -0400
-Subject: [PATCH] ipv6: Need to export ipv6_push_frag_opts for tunneling now.
-
-Since that change also made the nfrag function not necessary
-for exports, remove it.
-
-Fixes: 89a23c8b528b ("ip6_tunnel: Fix missing tunnel encapsulation limit option")
-Signed-off-by: David S. Miller <davem@davemloft.net>
----
- net/ipv6/exthdrs.c | 2 +-
- 1 file changed, 1 insertion(+), 1 deletion(-)
-
---- a/net/ipv6/exthdrs.c
-+++ b/net/ipv6/exthdrs.c
-@@ -729,13 +729,13 @@ void ipv6_push_nfrag_opts(struct sk_buff
- 	if (opt->hopopt)
- 		ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt);
- }
--EXPORT_SYMBOL(ipv6_push_nfrag_opts);
- 
- void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto)
- {
- 	if (opt->dst1opt)
- 		ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt);
- }
-+EXPORT_SYMBOL(ipv6_push_frag_opts);
- 
- struct ipv6_txoptions *
- ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt)