kernel: ip6_tunnel: use skb_vlan_inet_prepare() in __ip6_tnl_rcv()

In the Linux kernel, the following vulnerability has been resolved: ip6tunnel: use skbvlaninetprepare in ip6tnlrcv Blamed commit did not take care of VLAN encapsulations as spotted by syzbot 1. Use skbvlaninetprepare instead of pskbinetmaypull. 1 BUG: KMSAN: uninit-value in INETECNdecapsulate...