iio: imu: inv_mpu6050: use the common inv_sensors timestamp module

Replace timestamping by the new common inv_sensors timestamp
module. The principle behind is the same but the implementation in
the new module is far better providing less jitter and a better
estimation.

Signed-off-by: Jean-Baptiste Maneyrol <jean-baptiste.maneyrol@tdk.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20230606162147.79667-5-inv.git-commit@tdk.com


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