!5710 v2 ip6_tunnel: make sure to pull inner header in __ip6_tnl_rcv()

Merge Pull Request from: @ci-robot 
 
PR sync from: Dong Chenchen <dongchenchen2@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/Q42KETMRN3NI5IACE7RR257KGJYIGCJK/ 
 
https://gitee.com/src-openeuler/kernel/issues/I99JV2 
 
Link:https://gitee.com/openeuler/kernel/pulls/5710

 

Reviewed-by: Liu YongQiang <liuyongqiang13@huawei.com>
Signed-off-by: Zhang Changzhong <zhangchangzhong@huawei.com>