serial: 8250_bcm7271: balance clk_enable calls

The sw_baud clock must be disabled when the device driver is not
connected to the device. This now occurs when probe fails and
upon remove.

Fixes: 41a4694 ("serial: 8250: Add new 8250-core based Broadcom STB driver")
Reported-by: XuDong Liu <m202071377@hust.edu.cn>
Link: https://lore.kernel.org/lkml/20230424125100.4783-1-m202071377@hust.edu.cn/
Signed-off-by: Doug Berger <opendmb@gmail.com>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20230427181916.2983697-2-opendmb@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: Doug Berger

drivers/tty/serial/8250/8250_bcm7271.c

@@ -1032,7 +1032,7 @@ static int brcmuart_probe(struct platform_device *pdev)
 	if (clk_rate == 0) {
 		dev_err(dev, "clock-frequency or clk not defined\n");
 		ret = -EINVAL;
-		goto release_dma;
+		goto err_clk_disable;
 	}
 
 	dev_dbg(dev, "DMA is %senabled\n", priv->dma_enabled ? "" : "not ");
@@ -1119,6 +1119,8 @@ static int brcmuart_probe(struct platform_device *pdev)
 	serial8250_unregister_port(priv->line);
 err:
 	brcmuart_free_bufs(dev, priv);
+err_clk_disable:
+	clk_disable_unprepare(baud_mux_clk);
 release_dma:
 	if (priv->dma_enabled)
 		brcmuart_arbitration(priv, 0);
@@ -1133,6 +1135,7 @@ static int brcmuart_remove(struct platform_device *pdev)
 	hrtimer_cancel(&priv->hrt);
 	serial8250_unregister_port(priv->line);
 	brcmuart_free_bufs(&pdev->dev, priv);
+	clk_disable_unprepare(priv->baud_mux_clk);
 	if (priv->dma_enabled)
 		brcmuart_arbitration(priv, 0);
 	return 0;