Input: elantech - v4 is a clickpad, with only one button

Add pointer and buttonpad properties for v4 hardware.

Also, Jachiet reported that on Asus UX31, right button has no effect.
It turns out v4 has only one button, the right-button effect is
implemented with software when Windows driver is installed, or in
firmware when touchpad is in relative mode. So remove BTN_RIGHT
while at it.
Reported-by: NJachiet Louis <louis@jachiet.com>
Signed-off-by: NJJ Ding <jj_ding@emc.com.tw>
Reviewed-by: NChase Douglas <chase.douglas@canonical.com>
Signed-off-by: NDmitry Torokhov <dtor@mail.ru>

drivers/input/mouse/elantech.c

@@ -486,7 +486,6 @@ static void elantech_input_sync_v4(struct psmouse *psmouse)
 	unsigned char *packet = psmouse->packet;
 
 	input_report_key(dev, BTN_LEFT, packet[0] & 0x01);
-	input_report_key(dev, BTN_RIGHT, packet[0] & 0x02);
 	input_mt_report_pointer_emulation(dev, true);
 	input_sync(dev);
 }
@@ -967,6 +966,7 @@ static int elantech_set_input_params(struct psmouse *psmouse)
 	if (elantech_set_range(psmouse, &x_min, &y_min, &x_max, &y_max, &width))
 		return -1;
 
+	__set_bit(INPUT_PROP_POINTER, dev->propbit);
 	__set_bit(EV_KEY, dev->evbit);
 	__set_bit(EV_ABS, dev->evbit);
 	__clear_bit(EV_REL, dev->evbit);
@@ -1017,7 +1017,9 @@ static int elantech_set_input_params(struct psmouse *psmouse)
 			 */
 			psmouse_warn(psmouse, "couldn't query resolution data.\n");
 		}
-
+		/* v4 is clickpad, with only one button. */
+		__set_bit(INPUT_PROP_BUTTONPAD, dev->propbit);
+		__clear_bit(BTN_RIGHT, dev->keybit);
 		__set_bit(BTN_TOOL_QUADTAP, dev->keybit);
 		/* For X to recognize me as touchpad. */
 		input_set_abs_params(dev, ABS_X, x_min, x_max, 0, 0);