drm/amd: Keep display off while going into S4

drm/amd: Keep display off while going into S4

When userspace invokes S4 the flow is:

1) amdgpu_pmops_prepare()
2) amdgpu_pmops_freeze()
3) Create hibernation image
4) amdgpu_pmops_thaw()
5) Write out image to disk
6) Turn off system

Then on resume amdgpu_pmops_restore() is called.

This flow has a problem that because amdgpu_pmops_thaw() is called
it will call amdgpu_device_resume() which will resume all of the GPU.

This includes turning the display hardware back on and discovering
connectors again.

This is an unexpected experience for the display to turn back on.
Adjust the flow so that during the S4 sequence display hardware is
not turned back on.

Reported-by: Xaver Hugl <xaver.hugl@gmail.com>
Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/2038
Cc: Muhammad Usama Anjum <usama.anjum@collabora.com>
Tested-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Harry Wentland <harry.wentland@amd.com>
Link: https://lore.kernel.org/r/20250306185124.44780-1-mario.limonciello@amd.com
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>