drm/amd/display: Add sharpness control interface

- Add interface for controlling shapness level input into DCN.
- Update SPL to support custom sharpness values.
- Add support for different sharpness values depending on YUV/RGB
  content.

Reviewed-by: Samson Tam <samson.tam@amd.com>
Signed-off-by: Relja Vojvodic <Relja.Vojvodic@amd.com>
Signed-off-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>