drm/i915/gen11: Program the chroma upsampler for HDR planes.

We configure the chroma upsampler with the same chroma siting as
used by the scaler for consistency, the chroma upsampler is used
instead of the scaler for YUV 4:2:0 on ICL's HDR planes.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181018115134.9061-7-maarten.lankhorst@linux.intel.com