Revert "drm/amd: Keep display off while going into S4"

commit 68bfdc8d ("drm/amd: Keep display off while going into S4")
attempted to keep displays off during the S4 sequence by not resuming
display IP.  This however leads to hangs because DRM clients such as the
console can try to access registers and cause a hang.

Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/4155


Fixes: 68bfdc8d ("drm/amd: Keep display off while going into S4")
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Link: https://lore.kernel.org/r/20250522141328.115095-1-mario.limonciello@amd.com


Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit e485502c)
Cc: stable@vger.kernel.org