drm/amd/display: Update vactive margin and max vblank for fpo + vactive

drm/amd/display: Update vactive margin and max vblank for fpo + vactive

[Description]
- Some 1920x1080@60hz displays have VBLANK time > 600us which we
  still want to accept for FPO + Vactive configs based on testing
	- Increase max VBLANK time to 1000us to allow these configs
	  for FPO + Vactive
- Increase minimum vactive switch margin for FPO + Vactive to 200us
	- Based on testing, 1920x1080@120hz can have a switch margin
	  of ~160us which requires significantly longer FPO stretch
	  margin (5ms) which we don't want to accept for now
- Also move margins into debug option

Reviewed-by: Jun Lei <jun.lei@amd.com>
Reviewed-by: Nevenko Stupar <nevenko.stupar@amd.com>
Acked-by: Aurabindo Pillai <aurabindo.pillai@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>