drm/amd/display: Enable FPO for configs that could reduce vlevel

drm/amd/display: Enable FPO for configs that could reduce vlevel

[Description]
- On high refresh rate DRR displays that support VBLANK naturally,
  UCLK could be idling at DPM1 instead of DPM0 since it doesn't use
  FPO
- To achieve DPM0, enable FPO on these configs even though it can
  support P-State without FPO
- Default disable for now, have debug option to enable

Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Acked-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: Alvin Lee <Alvin.Lee2@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>