DRM: Armada: implement lastclose() for fbhelper

Call drm_fb_helper_restore_fbdev_mode() upon last close so that in the
event of the X server crashing, we have some kind of mode restored.

Reviewed-by: Rob Clark <robdclark@gmail.com>
Reviewed-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/drivers/gpu/drm/armada/armada_fbdev.c b/drivers/gpu/drm/armada/armada_fbdev.c
index dd5ea77..743570e 100644
--- a/drivers/gpu/drm/armada/armada_fbdev.c
+++ b/drivers/gpu/drm/armada/armada_fbdev.c
@@ -177,6 +177,16 @@
 	return ret;
 }
 
+void armada_fbdev_lastclose(struct drm_device *dev)
+{
+	struct armada_private *priv = dev->dev_private;
+
+	drm_modeset_lock_all(dev);
+	if (priv->fbdev)
+		drm_fb_helper_restore_fbdev_mode(priv->fbdev);
+	drm_modeset_unlock_all(dev);
+}
+
 void armada_fbdev_fini(struct drm_device *dev)
 {
 	struct armada_private *priv = dev->dev_private;