drm/amd/display: Revert "drm/amd/display: Add flag to detect dpms force off during HPD"

This reverts commit 035f5496.

The reverted commit was trying to fix side effect brought by
commit 3c4d55c9 ("drm/amd/display: turn DPMS off on connector unplug")

However,
* This reverted commit will have mst case never call dm_set_dpms_off()
  which conflicts the idea of original commit 3c4d55c9 ("drm/amd/display: turn DPMS off on connector unplug")
  That's due to dm_crtc_state is always null since the input parameter
  aconnector is the root device (source) of mst topology.  It's not an
  end stream sink within the mst topology.
* Setting dpms off should be triggered by usermode. Besdies, it seems
  usermode does release relevant resource for mst & non-mst case when
  unplug connecotr now. Which means we no longer need both commits now:
  commit 3c4d55c9 ("drm/amd/display: turn DPMS off on connector unplug")
  commit 035f5496 ("drm/amd/display: Add flag to detect dpms force off during HPD")

Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Reviewed-by: Aurabindo Jayamohanan Pillai <Aurabindo.Pillai@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Acked-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Wayne Lin <Wayne.Lin@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>