iio: imu: inv_mpu6050: fix an error code problem in inv_mpu6050_read_raw

iio: imu: inv_mpu6050: fix an error code problem in inv_mpu6050_read_raw

[ Upstream commit c3df0e29fb7788c4b3ddf37d5ed87dda2b822943 ]

inv_mpu6050_sensor_show() can return -EINVAL or IIO_VAL_INT. Return the
true value rather than only return IIO_VAL_INT.

Fixes: d5098447147c ("iio: imu: mpu6050: add calibration offset support")
Signed-off-by: Su Hui <suhui@nfschina.com>
Link: https://lore.kernel.org/r/20231030020218.65728-1-suhui@nfschina.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>