serial: ifx6x60: fix memory leak

If tty_register_driver() failed then tty_driver is still alive.
Free it with put_tty_driver().
Signed-off-by: Vasiliy Kulikov <segoon@openwall.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/serial/ifx6x60.c

@@ -1384,6 +1384,7 @@ static int __init ifx_spi_init(void)
 	if (result) {
 		pr_err("%s: tty_register_driver failed(%d)",
 			DRVNAME, result);
+		put_tty_driver(tty_drv);
 		return result;
 	}