drm/vc4: Don't use drm_put_dev

vc4 already has a proper load sequence, but the unload one needed some
fixups: First unregister, and last drop the final ref.
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>

drivers/gpu/drm/vc4/vc4_drv.c

@@ -279,12 +279,14 @@ static void vc4_drm_unbind(struct device *dev)
 	struct drm_device *drm = platform_get_drvdata(pdev);
 	struct vc4_dev *vc4 = to_vc4_dev(drm);
 
+	drm_dev_unregister(drm);
+
 	if (vc4->fbdev)
 		drm_fbdev_cma_fini(vc4->fbdev);
 
 	drm_mode_config_cleanup(drm);
 
-	drm_put_dev(drm);
+	drm_dev_unref(drm);
 }
 
 static const struct component_master_ops vc4_drm_ops = {