iio: imu: inv_icm42600: fix timestamp clock period by using lower value

iio: imu: inv_icm42600: fix timestamp clock period by using lower value

Clock period value is used for computing periods of sampling. There is
no need for it to be higher than the maximum odr, otherwise we are
losing precision in the computation for nothing.

Switch clock period value to maximum odr period (8kHz).

Fixes: 0ecc363ccea7 ("iio: make invensense timestamp module generic")
Cc: stable@vger.kernel.org
Signed-off-by: Jean-Baptiste Maneyrol <jean-baptiste.maneyrol@tdk.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>