drm/amdgpu: just suspend the hw on pci shutdown

We can't just reuse pci_remove as there may be userspace still
doing things.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=98638
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=97980
Reviewed-by: Christian König <christian.koenig@amd.com>
Reported-and-tested-by: Mike Lothian <mike@fireburn.co.uk>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index 3161d77..e41d4ba 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -1493,7 +1493,7 @@ static int amdgpu_fini(struct amdgpu_device *adev)
 	return 0;
 }
 
-static int amdgpu_suspend(struct amdgpu_device *adev)
+int amdgpu_suspend(struct amdgpu_device *adev)
 {
 	int i, r;