iio: imu: inv_mpu6050: fix frequency setting when chip is off

Track correctly FIFO state and apply ODR change before starting
the chip. Without the fix, you cannot change ODR more than 1 time
when data buffering is off. This restriction on a single pending ODR
change should only apply when the FIFO is on.

Fixes: 111e1abd ("iio: imu: inv_mpu6050: use the common inv_sensors timestamp module")
Cc: stable@vger.kernel.org
Signed-off-by: Jean-Baptiste Maneyrol <jean-baptiste.maneyrol@tdk.com>
Link: https://lore.kernel.org/r/20240219154741.90601-1-inv.git-commit@tdk.com


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