mm/damon: remove obsolete comments of kdamond_stop

Since commit 0f91d133 ("mm/damon: simplify stop mechanism") delete
kdamond_stop and change to use kthread stop mechanism, these obsolete
comments should be removed accordingly.

Link: https://lkml.kernel.org/r/20220531020421.46849-1-zhouchengming@bytedance.comSigned-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

include/linux/damon.h

@@ -397,7 +397,6 @@ struct damon_callback {
  * 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
@@ -406,14 +405,14 @@ struct damon_callback {
  * 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.