drm/amdgpu: fix backport of commit 73dae652

Commit 73dae652 ("drm/amdgpu: rework resume handling for display (v2)")
missed a small code change when it was backported resulting in an automatic
backlight control breakage.  Fix the backport.

Note that this patch is not in Linus' tree as it is not required there;
the bug was introduced in the backport.

Fixes: 99a02eab ("drm/amdgpu: rework resume handling for display (v2)")
Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/3853


Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org # 6.11.x
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>