iio: adc: ad7606: fix kernel-doc comments

iio: adc: ad7606: fix kernel-doc comments

Fix several issues with kernel-doc comments in ad7606.h:
* Add missing ":" to @param names.
* Fix order of @param names.
* Add some missing parameters.
* Remove some non-existent parameters.
* Fix alignment and wrapping.
* Fix some spelling.

`./scripts/kernel-doc -v -none drivers/iio/adc/ad7606*` is happy now.

Reviewed-by: Nuno Sá <nuno.sa@analog.com>
Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://patch.msgid.link/20250318-iio-adc-ad7606-improvements-v2-5-4b605427774c@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>