[media] uvcvideo: Add quirk to force the Oculus DK2 IR tracker to grayscale

This patch adds a quirk to force Y8 pixel format even if the camera reports
half-width YUYV.

Signed-off-by: Philipp Zabel <philipp.zabel@gmail.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

drivers/media/usb/uvc/uvcvideo.h

@@ -148,6 +148,7 @@
 #define UVC_QUIRK_PROBE_DEF		0x00000100
 #define UVC_QUIRK_RESTRICT_FRAME_RATE	0x00000200
 #define UVC_QUIRK_RESTORE_CTRLS_ON_INIT	0x00000400
+#define UVC_QUIRK_FORCE_Y8		0x00000800
 
 /* Format flags */
 #define UVC_FMT_FLAG_COMPRESSED		0x00000001