HID: hid-mulitouch: add support for the 'Sensing Win7-TwoFinger'

Added support for the 'Sensing Win7-TwoFinger' panel by GeneralTouch found on some tablets.

Because of conflicting VID/PID, this conflicts with previous support for some
single-touch panels by GeneralTouch

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@enac.fr>
Signed-off-by: Stéphane Chatty <chatty@enac.fr>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/hid/hid-ids.h

@@ -228,6 +228,7 @@
 #define USB_DEVICE_ID_GAMERON_DUAL_PCS_ADAPTOR	0x0002
 
 #define USB_VENDOR_ID_GENERAL_TOUCH	0x0dfc
+#define USB_DEVICE_ID_GENERAL_TOUCH_WIN7_TWOFINGERS 0x0001
 
 #define USB_VENDOR_ID_GLAB		0x06c2
 #define USB_DEVICE_ID_4_PHIDGETSERVO_30	0x0038