l2tp: prevent lockdep issue in l2tptunnelregister()
This is an automated ID intended to aid in discovery of potential security vulnerabilities. The actual impact and attack plausibility have not yet been proven. This ID is fixed in Linux Kernel version v5.10.166 by commit 16791d5a7a9ae5d0010fc751d2da6c57770889f4, it was introduced in version v5.10.166 by commit 2d77e5c0ad79004b5ef901895437e9cce6dfcc7e. For more details please see the references link.