mm/damon/core: update monitoring results for new monitoring attributes

region->nr_accesses is the number of sampling intervals in the last
aggregation interval that access to the region has found, and region->age
is the number of aggregation intervals that its access pattern has
maintained.  Hence, the real meaning of the two fields' values is
depending on current sampling and aggregation intervals.

This means the values need to be updated for every sampling and/or
aggregation intervals updates.  As DAMON core doesn't, it is a duty of
in-kernel DAMON framework applications like DAMON sysfs interface, or the
userspace users.

Handling it in userspace or in-kernel DAMON application is complicated,
inefficient, and repetitive compared to doing the update in DAMON core. 
Do the update in DAMON core.

Link: https://lkml.kernel.org/r/20230119013831.1911-3-sj@kernel.org


Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>