iio: imu: inv_mpu6050: fix FIFO parsing when empty

Now that we are reading the full FIFO in the interrupt handler,
it is possible to have an emply FIFO since we are still receiving
1 interrupt per data. Handle correctly this case instead of having
an error causing a reset of the FIFO.

Fixes: 0829edc4 ("iio: imu: inv_mpu6050: read the full fifo when processing data")
Cc: stable@vger.kernel.org
Signed-off-by: Jean-Baptiste Maneyrol <jean-baptiste.maneyrol@tdk.com>
Link: https://lore.kernel.org/r/20240219154825.90656-1-inv.git-commit@tdk.com


Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>