iio: adc: xilinx-ams: fix return error variable

Return irq instead of ret which always equals to zero here.

Fixes: d5c70627 ("iio: adc: Add Xilinx AMS driver")
Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Lv Ruyi <lv.ruyi@zte.com.cn>
Reviewed-by: Michal Simek <michal.simek@amd.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/xilinx-ams.c

@@ -1409,7 +1409,7 @@ static int ams_probe(struct platform_device *pdev)
 
 	irq = platform_get_irq(pdev, 0);
 	if (irq < 0)
-		return ret;
+		return irq;
 
 	ret = devm_request_irq(&pdev->dev, irq, &ams_irq, 0, "ams-irq",
 			       indio_dev);