drm/amd/display: Do not fail if build scaling params fails

[WHY]
Failing validation when building scaling parameters causes corruption to
occur due to pipe splitting with smaller pixel widths than HW supports.
This needs to fail silently for now to hide the corruption until the
corruption itself can be fixed.

[HOW]
Do not fail validation if building scaling params fails.

Signed-off-by: Sung Lee <sung.lee@amd.com>
Reviewed-by: Dmytro Laktyushkin <Dmytro.Laktyushkin@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>