drm/nouveau/runpm: fix module unload

Use the new vga_switcheroo_fini_domain_pm_ops function
to unregister the pm ops.

Based on a patch from:
Pali Rohár <pali.rohar@gmail.com>

bug:
https://bugzilla.kernel.org/show_bug.cgi?id=84431Reviewed-by: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Cc: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/nouveau_vga.c

@@ -108,7 +108,16 @@ void
 nouveau_vga_fini(struct nouveau_drm *drm)
 {
 	struct drm_device *dev = drm->dev;
+	bool runtime = false;
+
+	if (nouveau_runtime_pm == 1)
+		runtime = true;
+	if ((nouveau_runtime_pm == -1) && (nouveau_is_optimus() || nouveau_is_v1_dsm()))
+		runtime = true;
+
 	vga_switcheroo_unregister_client(dev->pdev);
+	if (runtime && nouveau_is_v1_dsm() && !nouveau_is_optimus())
+		vga_switcheroo_fini_domain_pm_ops(drm->dev->dev);
 	vga_client_register(dev->pdev, NULL, NULL, NULL);
 }