BT.2020 is an HDR color space and its luminance range doesn't match
that of the rest of the currently available color spaces. Without
support for white-point luminance in 5.14, there would be a behavior
change when luminance support is later introduced, so it is better to
remove it now, and reintroduce it when the necessary handling of
different luminance levels is available.
Change-Id: Ie29e4dd757faae3ac91d4252e1206acce42801dc
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>
89d0a03c06