drm/amd/display: Force always scale chroma, set always_scaled to false

This allows us to not always have scaling on, which causes issues with
validation and causes the text to blur slightly.

Signed-off-by: Andrew Jiang <Andrew.Jiang@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Harry Wentland <Harry.Wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>