drm/i915: Don't reject primary plane windowing with color keying enabled on SKL+

drm/i915: Don't reject primary plane windowing with color keying enabled on SKL+

commit 6f94b6dd006909a5ef6435cc0af557e945240f48 upstream.

On SKL+ plane scaling is mutually exclusive with color keying. The code
check for this, but during some refactoring the code got changed to
also reject primary plane windowing when color keying is used. There is
no such restriction in the hardware, so restore the original logic.

Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Fixes: 061e4b8d650a ("drm/i915: clean up atomic plane check functions, v2.")
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1452883613-28549-1-git-send-email-ville.syrjala@linux.intel.com
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
(cherry picked from commit 693bdc28a733dba68b86af295e7509812fec35d9)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>