drm/nouveau: Unregister switcheroo client on exit

Currently nouveau only registers as a vga_switcheroo client, but never
unregisters. This patch adds the necessary unregister calls.

Signed-off-by: Andreas Heider <andreas@meetr.de>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
diff --git a/drivers/gpu/drm/nouveau/nouveau_state.c b/drivers/gpu/drm/nouveau/nouveau_state.c
index e23c053..19706f0 100644
--- a/drivers/gpu/drm/nouveau/nouveau_state.c
+++ b/drivers/gpu/drm/nouveau/nouveau_state.c
@@ -840,6 +840,7 @@
 out_display_early:
 	engine->display.late_takedown(dev);
 out:
+	vga_switcheroo_unregister_client(dev->pdev);
 	vga_client_register(dev->pdev, NULL, NULL, NULL);
 	return ret;
 }
@@ -895,6 +896,7 @@
 
 	nouveau_irq_fini(dev);
 
+	vga_switcheroo_unregister_client(dev->pdev);
 	vga_client_register(dev->pdev, NULL, NULL, NULL);
 }