iio: imu: st_lsm6dsx: fix ODR check in st_lsm6dsx_write_raw

Since st_lsm6dsx i2c master controller relies on accel device as trigger
and slave devices can run at different ODRs we must select an accel_odr >=
slave_odr. Report real accel ODR in st_lsm6dsx_check_odr() in order to
properly set sensor frequency in st_lsm6dsx_write_raw and avoid to
report unsupported frequency

Fixes: 6ffb55e5 ("iio: imu: st_lsm6dsx: introduce ST_LSM6DSX_ID_EXT sensor ids")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c

@@ -1377,8 +1377,7 @@ int st_lsm6dsx_check_odr(struct st_lsm6dsx_sensor *sensor, u16 odr, u8 *val)
 		return -EINVAL;
 
 	*val = odr_table->odr_avl[i].val;
-
-	return 0;
+	return odr_table->odr_avl[i].hz;
 }
 
 static u16 st_lsm6dsx_check_odr_dependency(struct st_lsm6dsx_hw *hw, u16 odr,
@@ -1542,8 +1541,10 @@ static int st_lsm6dsx_write_raw(struct iio_dev *iio_dev,
 	case IIO_CHAN_INFO_SAMP_FREQ: {
 		u8 data;
 
-		err = st_lsm6dsx_check_odr(sensor, val, &data);
-		if (!err)
+		val = st_lsm6dsx_check_odr(sensor, val, &data);
+		if (val < 0)
+			err = val;
+		else
 			sensor->odr = val;
 		break;
 	}