Latest Thinkpad laptops use the HKEY_HID LEN0268 instead of the
LEN0068, as a result neither audio mute led nor mic mute led can work
any more.

After adding the new HKEY_HID into the is_thinkpad(), both of them
works well as before.

Cc: <stable@vger.kernel.org>
Signed-off-by: Hui Wang <hui.wang@canonical.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>