mei: docs: add missing entries to kdoc in struct mei_cfg_idx

Document all entries in struct mei_cfg_idx.

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/20231011074301.223879-3-tomas.winkler@intel.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>