HID: hid-multitouch: add support for the IDEACOM 6650 chip

The IDEACOM 6650 multitouch chip, present in various all-in-one computers,
uses the serial version of the HID multitouch protocol. No existing class
supports this.

In principle, the new MT_CLS_SERIAL should work for other
serial panels as well, perhaps including some eGalax panels.

Signed-off-by: Stephane Chatty <chatty@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 637e6e9..33b9834 100644
--- a/drivers/hid/hid-ids.h
+++ b/drivers/hid/hid-ids.h
@@ -347,6 +347,9 @@
 #define USB_DEVICE_ID_UGCI_FLYING	0x0020
 #define USB_DEVICE_ID_UGCI_FIGHTING	0x0030
 
+#define USB_VENDOR_ID_IDEACOM		0x1cb6
+#define USB_DEVICE_ID_IDEACOM_IDC6650	0x6650
+
 #define USB_VENDOR_ID_ILITEK		0x222a
 #define USB_DEVICE_ID_ILITEK_MULTITOUCH	0x0001