Docs/admin-guide/mm/damon/usage: update for schemes statistics

This updates DAMON debugfs interface for statistics of schemes
successfully applied regions and time/space quota limit exceeds counts.

Link: https://lkml.kernel.org/r/20211210150016.35349-7-sj@kernel.org


Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>