Input: synaptics - whitelist Lenovo T580 SMBus intertouch

Adds the Lenovo T580 to the SMBus intertouch list for Synaptics
touchpads. I've tested with this for a week now, and it seems a great
improvement. It's also nice to have the complaint gone from dmesg.

Signed-off-by: Nick Black <dankamongmen@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/mouse/synaptics.c

@@ -178,6 +178,7 @@ static const char * const smbus_pnp_ids[] = {
 	"LEN0092", /* X1 Carbon 6 */
 	"LEN0096", /* X280 */
 	"LEN0097", /* X280 -> ALPS trackpoint */
+	"LEN009b", /* T580 */
 	"LEN200f", /* T450s */
 	"SYN3052", /* HP EliteBook 840 G4 */
 	"SYN3221", /* HP 15-ay000 */