ip6_tunnel: Correct tos value in collect_md mode

Same as ip_gre, geneve and vxlan, use key->tos as traffic class value.

CC: Peter Dawson <petedaws@gmail.com>
Fixes: 0e9a7095 ("ip6_tunnel, ip6_gre: fix setting of DSCP on
encapsulated packets”)
Signed-off-by: NHaishuang Yan <yanhaishuang@cmss.chinamobile.com>
Acked-by: NPeter Dawson <peter.a.dawson@boeing.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv6/ip6_tunnel.c

@@ -1248,7 +1248,7 @@ ip4ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
 		fl6.flowi6_proto = IPPROTO_IPIP;
 		fl6.daddr = key->u.ipv6.dst;
 		fl6.flowlabel = key->label;
-		dsfield = ip6_tclass(key->label);
+		dsfield =  key->tos;
 	} else {
 		if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))
 			encap_limit = t->parms.encap_limit;
@@ -1319,7 +1319,7 @@ ip6ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
 		fl6.flowi6_proto = IPPROTO_IPV6;
 		fl6.daddr = key->u.ipv6.dst;
 		fl6.flowlabel = key->label;
-		dsfield = ip6_tclass(key->label);
+		dsfield = key->tos;
 	} else {
 		offset = ip6_tnl_parse_tlv_enc_lim(skb, skb_network_header(skb));
 		/* ip6_tnl_parse_tlv_enc_lim() might have reallocated skb->head */