Input: synaptics - switch another X1 Carbon 6 to RMI/SMbus

Some Lenovo X1 Carbon Gen 6 laptops report LEN0091. Add this
to the smbus_pnp_ids list.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20191119105118.54285-2-hverkuil-cisco@xs4all.nl
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>