HID: hid-multitouch: add support for PenMount dual-touch panel

This patch adds PenMount support to hid-multitouch.  A new class
MT_CLS_CONFIDENCE is defined for PenMount, since it uses HID_DG_CONFIDENCE as
the valid flag.

Signed-off-by: John Sung <penmount.touch@gmail.com>
[benjamin.tissoires@enac.fr: rebased on top of last_index_field changes]
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@enac.fr>
Acked-by: Henrik Rydberg <rydberg@euromail.se>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/drivers/hid/hid-ids.h b/drivers/hid/hid-ids.h
index d485894..252aeba 100644
--- a/drivers/hid/hid-ids.h
+++ b/drivers/hid/hid-ids.h
@@ -484,6 +484,9 @@
 #define USB_VENDOR_ID_PANTHERLORD	0x0810
 #define USB_DEVICE_ID_PANTHERLORD_TWIN_USB_JOYSTICK	0x0001
 
+#define USB_VENDOR_ID_PENMOUNT		0x14e1
+#define USB_DEVICE_ID_PENMOUNT_PCI	0x3500
+
 #define USB_VENDOR_ID_PETALYNX		0x18b1
 #define USB_DEVICE_ID_PETALYNX_MAXTER_REMOTE	0x0037