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.nlSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/mouse/synaptics.c

@@ -172,6 +172,7 @@ static const char * const smbus_pnp_ids[] = {
 	"LEN0071", /* T480 */
 	"LEN0072", /* X1 Carbon Gen 5 (2017) - Elan/ALPS trackpoint */
 	"LEN0073", /* X1 Carbon G5 (Elantech) */
+	"LEN0091", /* X1 Carbon 6 */
 	"LEN0092", /* X1 Carbon 6 */
 	"LEN0093", /* T480 */
 	"LEN0096", /* X280 */