iio: adc: ad7266: Fix variable checking bug

The ret variable was not checked after iio_device_release_direct_mode(),
which could possibly cause errors

Fixes: c70df20e ("iio: adc: ad7266: claim direct mode during sensor read")
Signed-off-by: Fernando Yang <hagisf@usp.br>
Link: https://lore.kernel.org/r/20240603180757.8560-1-hagisf@usp.br
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/ad7266.c

@@ -157,6 +157,8 @@ static int ad7266_read_raw(struct iio_dev *indio_dev,
 		ret = ad7266_read_single(st, val, chan->address);
 		iio_device_release_direct_mode(indio_dev);
 
+		if (ret < 0)
+			return ret;
 		*val = (*val >> 2) & 0xfff;
 		if (chan->scan_type.sign == 's')
 			*val = sign_extend32(*val,