drm/amd/display: Enable dcn314 DPP RCO

[Why and How]
Add back debug bits enabling RCO for dcn314 as underflow
associated with this change has been resolved

Acked-by: Stylon Wang <stylon.wang@amd.com>
Signed-off-by: Daniel Miess <daniel.miess@amd.com>
Reviewed-by: Jun Lei <jun.lei@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>