Input: synaptics - enable SMBus for HP Elitebook 850 G1

The kernel reports that the touchpad for this device can support
SMBus mode.

Reported-by: jt <enopatch@gmail.com>
Link: https://lore.kernel.org/r/iys5dbv3ldddsgobfkxldazxyp54kay4bozzmagga6emy45jop@2ebvuxgaui4u


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