mm/damon/core: pass per-region filter-passed bytes to damos_walk_control->walk_fn()

Total size of memory that passed DAMON operations set layer-handled DAMOS
filters per scheme is provided to DAMON core API and ABI (sysfs interface)
users.  Having it per-region in non-accumulated way can provide it in
finer granularity.  Provide it to damos_walk() core API users, by passing
the data to damos_walk_control->walk_fn().

Link: https://lkml.kernel.org/r/20250106193401.109161-13-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>