serial/imx: propagate error of platform_driver_register in init routine

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/tty/serial/imx.c

@@ -1476,7 +1476,7 @@ static int __init imx_serial_init(void)
 	if (ret != 0)
 		uart_unregister_driver(&imx_reg);
 
-	return 0;
+	return ret;
 }
 
 static void __exit imx_serial_exit(void)