iio: imu: inv_icm42600: add support of accel low-power mode

iio: imu: inv_icm42600: add support of accel low-power mode

Add ODRs accessible only in low-power mode. Switch automatically to
low-power or low-noise depending on the ODR set.

Add channel attributes "power_mode" and "power_mode_available" for
setting the power mode to use (low-noise or low-power) for ODRs
supporting both mode. Reading "power_mode" when the sensor is on
will return the actual mode and not the requested one. It will be
different when using ODRs not supported by the requested mode.

Use low-power mode by default.

Signed-off-by: Jean-Baptiste Maneyrol <jean-baptiste.maneyrol@tdk.com>
Link: https://lore.kernel.org/r/20240605195949.766677-3-inv.git-commit@tdk.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>