iio: imu: fxos8700: fix incomplete ACCEL and MAGN channels readback

The length of ACCEL and MAGN 3-axis channels output data is 6 byte
individually. However block only read 3 bytes data into buffer from
ACCEL or MAGN output data registers every time. It causes an incomplete
ACCEL and MAGN channels readback.

Set correct value count for regmap_bulk_read to get 6 bytes ACCEL and
MAGN channels readback.

Fixes: 84e5ddd ("iio: imu: Add support for the FXOS8700 IMU")
Signed-off-by: Carlos Song <carlos.song@nxp.com>
Link: https://lore.kernel.org/r/20221208071911.2405922-4-carlos.song@nxp.com
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Author: NXP-CarlosSong

drivers/iio/imu/fxos8700_core.c

@@ -414,7 +414,7 @@ static int fxos8700_get_data(struct fxos8700_data *data, int chan_type,
 
 	/* Block read 6 bytes of device output registers to avoid data loss */
 	ret = regmap_bulk_read(data->regmap, base, data->buf,
-			       FXOS8700_DATA_BUF_SIZE);
+			       sizeof(data->buf));
 	if (ret)
 		return ret;