thinkpad-acpi: module autoloading for newer Lenovo ThinkPads.

The newer Lenovo ThinkPads have HKEY HID of LEN0068 instead
of IBM0068. Added new HID so that thinkpad_acpi module will
auto load on these newer Lenovo ThinkPads.

Acked-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: stable@kernel.org
Signed-off-by: Manoj Iyer <manoj.iyer@canonical.com>
Signed-off-by: Andy Lutomirski <luto@mit.edu>
Signed-off-by: Matthew Garrett <mjg@redhat.com>