mm/damon: remove obsolete comments of kdamond_stop

 * detail.

 *

 * @kdamond:		Kernel thread who does the monitoring.

 * @kdamond_stop:	Notifies whether kdamond should stop.

 * @kdamond_lock:	Mutex for the synchronizations with @kdamond.

 *

 * For each monitoring context, one kernel thread for the monitoring is

 * Once started, the monitoring thread runs until explicitly required to be

 * terminated or every monitoring target is invalid.  The validity of the

 * targets is checked via the &damon_operations.target_valid of @ops.  The

 * termination can also be explicitly requested by writing non-zero to

 * @kdamond_stop.  The thread sets @kdamond to NULL when it terminates.

 * Therefore, users can know whether the monitoring is ongoing or terminated by

 * reading @kdamond.  Reads and writes to @kdamond and @kdamond_stop from

 * outside of the monitoring thread must be protected by @kdamond_lock.

 *

 * Note that the monitoring thread protects only @kdamond and @kdamond_stop via

 * @kdamond_lock.  Accesses to other fields must be protected by themselves.

 * termination can also be explicitly requested by calling damon_stop().

 * The thread sets @kdamond to NULL when it terminates. Therefore, users can

 * know whether the monitoring is ongoing or terminated by reading @kdamond.

 * Reads and writes to @kdamond from outside of the monitoring thread must

 * be protected by @kdamond_lock.

 *

 * Note that the monitoring thread protects only @kdamond via @kdamond_lock.

 * Accesses to other fields must be protected by themselves.

 *

 * @ops:	Set of monitoring operations for given use cases.

 * @callback:	Set of callbacks for monitoring events notifications.