[media] videodev2.h: improve colorspace support

Add support for the new AdobeRGB and BT.2020 colorspaces as needed for
HDMI 2.0.

Add support to specify the Y'CbCr encoding and quantization range explicitly.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>