Input: synaptics - fix regression with "image sensor" trackpads

commit 7968a5dd492ccc38345013e534ad4c8d6eb60ed1
Input: synaptics - add support for Relative mode

Accidentally broke support for advanced gestures (multitouch)
on some trackpads such as the one in my ThinkPad X220 by
incorretly changing the condition for enabling them. This
restores it.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: stable@kernel.org [3.3]
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

drivers/input/mouse/synaptics.c

@@ -274,7 +274,8 @@ static int synaptics_set_advanced_gesture_mode(struct psmouse *psmouse)
 	static unsigned char param = 0xc8;
 	struct synaptics_data *priv = psmouse->private;
 
-	if (!SYN_CAP_ADV_GESTURE(priv->ext_cap_0c))
+	if (!(SYN_CAP_ADV_GESTURE(priv->ext_cap_0c) ||
+	      SYN_CAP_IMAGE_SENSOR(priv->ext_cap_0c)))
 		return 0;
 
 	if (psmouse_sliced_command(psmouse, SYN_QUE_MODEL))