tty: serial: linflexuart: Remove redundant check to simplify the code

In the function uart_add_one_port(), it can return zero or non-zero,
so remove redundant check to simplify the code.

Signed-off-by: Zhang Shengju <zhangshengju@cmss.chinamobile.com>
Signed-off-by: Tang Bin <tangbin@cmss.chinamobile.com>
Link: https://lore.kernel.org/r/20210823110754.11232-1-tangbin@cmss.chinamobile.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/fsl_linflexuart.c

@@ -861,11 +861,7 @@ static int linflex_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, sport);
 
-	ret = uart_add_one_port(&linflex_reg, sport);
-	if (ret)
-		return ret;
-
-	return 0;
+	return uart_add_one_port(&linflex_reg, sport);
 }
 
 static int linflex_remove(struct platform_device *pdev)