Revert "drm/amd/display: fix dpms_off issue when disabling bios mode"

This reverts commit 58e67bb3.

This patch was reverted, but came back again as
commit 58e67bb3 ("drm/amd/display: fix dpms_off issue when disabling bios mode")
Revert it again as it breaks Asus G513QY / 6800M laptops.

Bug: drm/amd#2259


Cc: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Cc: Zhongwei <Zhongwei.Zhang@amd.com>
Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Mike Lothian <mike@fireburn.co.uk>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>