drm/i915/icl: Enable Plane Input CSC for YUV to RGB Conversion

drm/i915/icl: Enable Plane Input CSC for YUV to RGB Conversion

Plane input CSC needs to be enabled to convert frambuffers from
YUV to RGB. This is needed for bottom 3 planes on ICL, rest of
the planes have hardcoded conversion and taken care by the legacy
code.

This patch defines the co-efficient values for YUV to RGB conversion
in BT709 and BT601 formats. It programs the coefficients and enables
the plane input csc unit in hardware.

This has been verified and tested by Maarten and the change is working
as expecpted.

v2: Addressed Maarten's and Ville's review comments and added the
coefficients in a 2D array instead of independent Macros.

v3: Added individual coefficient matrix (9 values) instead of 6
register values as per Maarten's comment. Also addresed a shift
issue with B channel coefficient.

v4: Added support for Limited Range Color Handling

v5: Fixed Matt and Maarten's review comments.

v6: Added human readable matrix values for YUV to RGB Conversion along
with just the bspec register values, as per Matt's suggestion.

v7: Refactored the code, move csc coefficient programming function to
intel_sprite.c and made it static as per Ville's review comment.

v8: Addressed Ville's review comment. Called the coefficient programming
from within the skl_program_plane and used I915_WRITE_FW instead of
I915_WRITE.

v9: Fixed Ville's review comments.

Signed-off-by: Uma Shankar <uma.shankar@intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1541099420-12419-3-git-send-email-uma.shankar@intel.com