Input: synaptics - enable SMBus for HP Elitebook 840 G2

The kernel reports that the touchpad for this device can support a
different bus.

With SMBus enabled the touchpad movement is smoother and three-finger
gestures are recognized.
Signed-off-by: Jonathan Denose <jdenose@google.com>
Link: https://lore.kernel.org/r/20240719180612.1.Ib652dd808c274076f32cd7fc6c1160d2cf71753b@changeidSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/mouse/synaptics.c

@@ -189,6 +189,7 @@ static const char * const smbus_pnp_ids[] = {
 	"LEN2054", /* E480 */
 	"LEN2055", /* E580 */
 	"LEN2068", /* T14 Gen 1 */
+	"SYN3015", /* HP EliteBook 840 G2 */
 	"SYN3052", /* HP EliteBook 840 G4 */
 	"SYN3221", /* HP 15-ay000 */
 	"SYN323d", /* HP Spectre X360 13-w013dx */