Add kerneldoc and sysfs class documentation.

Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Kurt Borja <kuurtb@gmail.com>
Reviewed-by: Mark Pearson <mpearson-lenovo@squebb.ca>
Tested-by: Mark Pearson <mpearson-lenovo@squebb.ca>
Link: https://lore.kernel.org/r/20250116002721.75592-19-kuurtb@gmail.com


Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>