HID: multitouch: Add quirk for VTL touch panels

VTL panels do not switch to the multitouch mode until the input mode
feature is read by the host. This should normally be done by
usbhid, but it looks like an other bug prevents usbhid to properly
retrieve the feature state. As a workaround, we force the reading of
the feature in mt_set_input_mode for such devices.

Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Mathieu Magnaudet <mathieu.magnaudet@enac.fr>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/drivers/hid/hid-ids.h b/drivers/hid/hid-ids.h
index 7c86373..d6cc6a9 100644
--- a/drivers/hid/hid-ids.h
+++ b/drivers/hid/hid-ids.h
@@ -931,6 +931,9 @@
 #define USB_DEVICE_ID_VERNIER_CYCLOPS	0x0004
 #define USB_DEVICE_ID_VERNIER_LCSPEC	0x0006
 
+#define USB_VENDOR_ID_VTL		0x0306
+#define USB_DEVICE_ID_VTL_MULTITOUCH_FF3F	0xff3f
+
 #define USB_VENDOR_ID_WACOM		0x056a
 #define USB_DEVICE_ID_WACOM_GRAPHIRE_BLUETOOTH	0x81
 #define USB_DEVICE_ID_WACOM_INTUOS4_BLUETOOTH   0x00BD