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 <[e-mail]>
Reported-and-tested-by: Mike Lothian <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

drivers/gpu/drm/amd/amdgpu/amdgpu.h

···
 				 struct drm_file *file_priv);
 void amdgpu_driver_preclose_kms(struct drm_device *dev,
 				struct drm_file *file_priv);
+int amdgpu_suspend(struct amdgpu_device *adev);
 int amdgpu_device_suspend(struct drm_device *dev, bool suspend, bool fbcon);
 int amdgpu_device_resume(struct drm_device *dev, bool resume, bool fbcon);
 u32 amdgpu_get_vblank_counter_kms(struct drm_device *dev, unsigned int pipe);

drivers/gpu/drm/amd/amdgpu/amdgpu_device.c

···
 	return 0;
 }
 
-static int amdgpu_suspend(struct amdgpu_device *adev)
+int amdgpu_suspend(struct amdgpu_device *adev)
 {
 	int i, r;
 

drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c

···
 static void
 amdgpu_pci_shutdown(struct pci_dev *pdev)
 {
+	struct drm_device *dev = pci_get_drvdata(pdev);
+	struct amdgpu_device *adev = dev->dev_private;
+
 	/* if we are running in a VM, make sure the device
 	 * torn down properly on reboot/shutdown.
 	 * unfortunately we can't detect certain
 	 * hypervisors so just do this all the time.
 	 */
-	amdgpu_pci_remove(pdev);
+	amdgpu_suspend(adev);
 }
 
 static int amdgpu_pmops_suspend(struct device *dev)