drm: bridge: analogix: Detach panel when unbinding analogix dp

The panel is attached when binding analogix dp.

Signed-off-by: Jeffy Chen <jeffy.chen@rock-chips.com>
Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: http://patchwork.freedesktop.org/patch/msgid/1491481885-13775-2-git-send-email-jeffy.chen@rock-chips.com

drivers/gpu/drm/bridge/analogix/analogix_dp_core.c

@@ -1443,6 +1443,8 @@ void analogix_dp_unbind(struct device *dev, struct device *master,
 	if (dp->plat_data->panel) {
 		if (drm_panel_unprepare(dp->plat_data->panel))
 			DRM_ERROR("failed to turnoff the panel\n");
+		if (drm_panel_detach(dp->plat_data->panel))
+			DRM_ERROR("failed to detach the panel\n");
 	}
 
 	pm_runtime_disable(dev);