serial: liteuart: fix minor-number leak on probe errors

Make sure to release the allocated minor number before returning on
probe errors.

Fixes: 1da81e55 ("drivers/tty/serial: add LiteUART driver")
Cc: stable@vger.kernel.org      # 5.11
Cc: Filip Kokosinski <fkokosinski@antmicro.com>
Cc: Mateusz Holenko <mholenko@antmicro.com>
Reviewed-by: Stafford Horne <shorne@gmail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20211117100512.5058-3-johan@kernel.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/liteuart.c

@@ -270,8 +270,10 @@ static int liteuart_probe(struct platform_device *pdev)
 
 	/* get membase */
 	port->membase = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
-	if (IS_ERR(port->membase))
-		return PTR_ERR(port->membase);
+	if (IS_ERR(port->membase)) {
+		ret = PTR_ERR(port->membase);
+		goto err_erase_id;
+	}
 
 	/* values not from device tree */
 	port->dev = &pdev->dev;
@@ -287,7 +289,16 @@ static int liteuart_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, port);
 
-	return uart_add_one_port(&liteuart_driver, &uart->port);
+	ret = uart_add_one_port(&liteuart_driver, &uart->port);
+	if (ret)
+		goto err_erase_id;
+
+	return 0;
+
+err_erase_id:
+	xa_erase(&liteuart_array, uart->id);
+
+	return ret;
 }
 
 static int liteuart_remove(struct platform_device *pdev)