drm: panel: simple: add missing platform_driver_unregister() in panel_simple_init

Add the missing platform_driver_unregister() before return
from panel_simple_init in the error handling case when failed
to register panel_simple_dsi_driver with CONFIG_DRM_MIPI_DSI
enabled.
Signed-off-by: Qinglang Miao <miaoqinglang@huawei.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20201031011856.137307-1-miaoqinglang@huawei.com

drivers/gpu/drm/panel/panel-simple.c

@@ -4675,8 +4675,10 @@ static int __init panel_simple_init(void)
 
 	if (IS_ENABLED(CONFIG_DRM_MIPI_DSI)) {
 		err = mipi_dsi_driver_register(&panel_simple_dsi_driver);
-		if (err < 0)
+		if (err < 0) {
+			platform_driver_unregister(&panel_simple_platform_driver);
 			return err;
+		}
 	}
 
 	return 0;