mm/damon/paddr: report filter-passed bytes back for normal actions

damon_operations->apply_scheme() implementations are requested to report
back how many bytes of the given region has passed DAMOS filter.  'paddr'
operations set implementation supports some of region-internal DAMOS
filter handling for normal DAMOS actions except DAMOS_STAT action.  But,
those are not respecting the request.  Report the region-internal DAMOS
filter-passed bytes back for the actions.

Link: https://lkml.kernel.org/r/20250106193401.109161-6-sj@kernel.org


Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>