HID: wacom: Add a new Art Pen 2

Signed-off-by: Ping Cheng <[e-mail]>
Signed-off-by: Jiri Kosina <[e-mail]>

drivers/hid/wacom_wac.c

···
 	case 0x885:	/* Intuos3 Marker Pen */
 	case 0x804:	/* Intuos4/5 13HD/24HD Marker Pen */
 	case 0x10804:	/* Intuos4/5 13HD/24HD Art Pen */
+	case 0x204:     /* Art Pen 2 */
 		is_art_pen = true;
 		break;
 	}