iio: adc: Add check for devm_request_threaded_irq

As the potential failure of the devm_request_threaded_irq(),
it should be better to check the return value and return
error if fails.

Fixes: fa659a40 ("iio: adc: twl6030-gpadc: Use devm_* API family")
Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
Link: https://lore.kernel.org/r/20220224062849.3280966-1-jiasheng@iscas.ac.cnSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/twl6030-gpadc.c

@@ -911,6 +911,8 @@ static int twl6030_gpadc_probe(struct platform_device *pdev)
 	ret = devm_request_threaded_irq(dev, irq, NULL,
 				twl6030_gpadc_irq_handler,
 				IRQF_ONESHOT, "twl6030_gpadc", indio_dev);
+	if (ret)
+		return ret;
 
 	ret = twl6030_gpadc_enable_irq(TWL6030_GPADC_RT_SW1_EOC_MASK);
 	if (ret < 0) {