iio: imu: inv_icm42600: fix odr switch when turning buffer off

iio: imu: inv_icm42600: fix odr switch when turning buffer off

ODR switch is done in 2 steps when FIFO is on : change the ODR register
value and acknowledge change when reading the FIFO ODR change flag.
When we are switching odr and turning buffer off just afterward, we are
losing the FIFO ODR change flag and ODR switch is blocked.

Fix the issue by force applying any waiting ODR change when turning
buffer off.

Fixes: ec74ae9fd37c ("iio: imu: inv_icm42600: add accurate timestamping")
Signed-off-by: Jean-Baptiste Maneyrol <jean-baptiste.maneyrol@tdk.com>
Cc: stable@vger.kernel.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>