staging: iio: cdc: simplify return flow

Simplify return flow ad7150_write_event_params in order to reduce code length.
Since i2c_smbus_write_word_data only returns a negative value or 0 the change is safe.

This patch fixes the following coccicheck warning:

drivers/staging/iio/cdc/ad7150.c:182:2-5: WARNING: end returns can be simpified if negative or 0 value
Signed-off-by: Ioana Ciornei <ciorneiioana@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/iio/cdc/ad7150.c

@@ -179,12 +179,9 @@ static int ad7150_write_event_params(struct iio_dev *indio_dev,
 		/* Note completely different from the adaptive versions */
 	case IIO_EV_TYPE_THRESH:
 		value = chip->threshold[rising][chan];
-		ret = i2c_smbus_write_word_data(chip->client,
+		return i2c_smbus_write_word_data(chip->client,
 						ad7150_addresses[chan][3],
 						swab16(value));
-		if (ret < 0)
-			return ret;
-		return 0;
 	case IIO_EV_TYPE_MAG_ADAPTIVE:
 		sens = chip->mag_sensitivity[rising][chan];
 		timeout = chip->mag_timeout[rising][chan];