mfd: ti_am335x_tscadc: Delete superfluous error message

In the function ti_tscadc_probe(), when get irq failed,
platform_get_irq() logs an error message, so remove
redundant message here.
Signed-off-by: Tang Bin <tangbin@cmss.chinamobile.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/ti_am335x_tscadc.c

@@ -175,10 +175,9 @@ static	int ti_tscadc_probe(struct platform_device *pdev)
 	tscadc->dev = &pdev->dev;
 
 	err = platform_get_irq(pdev, 0);
-	if (err < 0) {
-		dev_err(&pdev->dev, "no irq ID is specified.\n");
+	if (err < 0)
 		goto ret;
-	} else
+	else
 		tscadc->irq = err;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);