iio: imu: inv_icm42600: delete unneeded update watermark call

Update watermark will be done inside the hwfifo_set_watermark callback
just after the update_scan_mode. It is useless to do it here.

Fixes: 7f85e42a

 ("iio: imu: inv_icm42600: add buffer support in iio devices")
Cc: stable@vger.kernel.org
Signed-off-by: Jean-Baptiste Maneyrol <jean-baptiste.maneyrol@tdk.com>
Link: https://lore.kernel.org/r/20240527210008.612932-1-inv.git-commit@tdk.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>