Revert "drm/amd/pm: resolve reboot exception for si oland"

commit 95555803 upstream.

This reverts commit e490d60a.

This causes hangs on SI when DC is enabled and errors on driver
reboot and power off cycles.

Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/3216
Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/2755


Reviewed-by: Yang Wang <kevinyang.wang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>