[media] vivid.txt: document new controls

Document the new 'Y'CbCr Encoding' and 'Quantization' controls.
Signed-off-by: NHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@osg.samsung.com>

Documentation/video4linux/vivid.txt

@@ -640,6 +640,21 @@ Colorspace: selects which colorspace should be used when generating the image.
 	Changing the colorspace will result in the V4L2_EVENT_SOURCE_CHANGE
 	to be sent since it emulates a detected colorspace change.
 
+Y'CbCr Encoding: selects which Y'CbCr encoding should be used when generating
+	a Y'CbCr image.	This only applies if the CSC Colorbar test pattern is
+	selected, and if the format is set to a Y'CbCr format as opposed to an
+	RGB format.
+
+	Changing the Y'CbCr encoding will result in the V4L2_EVENT_SOURCE_CHANGE
+	to be sent since it emulates a detected colorspace change.
+
+Quantization: selects which quantization should be used for the RGB or Y'CbCr
+	encoding when generating the test pattern. This only applies if the CSC
+	Colorbar test pattern is selected.
+
+	Changing the quantization will result in the V4L2_EVENT_SOURCE_CHANGE
+	to be sent since it emulates a detected colorspace change.
+
 Limited RGB Range (16-235): selects if the RGB range of the HDMI source should
 	be limited or full range. This combines with the Digital Video 'Rx RGB
 	Quantization Range' control and can be used to test what happens if