tty: serial: 8250_mtk: Use PTR_ERR_OR_ZERO

Use PTR_ERR_OR_ZERO rather than if(IS_ERR(...)) + PTR_ERR
Signed-off-by: NHimanshu Jha <himanshujha199640@gmail.com>
Reviewed-by: NMatthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/8250/8250_mtk.c

@@ -171,10 +171,7 @@ static int mtk8250_probe_of(struct platform_device *pdev, struct uart_port *p,
 	}
 
 	data->bus_clk = devm_clk_get(&pdev->dev, "bus");
-	if (IS_ERR(data->bus_clk))
-		return PTR_ERR(data->bus_clk);
-
-	return 0;
+	return PTR_ERR_OR_ZERO(data->bus_clk);
 }
 
 static int mtk8250_probe(struct platform_device *pdev)