Revert "Revert "Tethering: IPV6 tethering support""

This reverts commit 0d56c199166f136c5888dabab3775233c8acb38f.
Revert "Revert "Tethering: IPV6 tethering support""

This reverts commit 46dcf06235953a703c85a2c15ceeee4bb4cb9356.
Revert "Tethering: IPV6 tethering support"

This reverts commit e078591e742b134b510354b4fff71aca08c33130.