mm/damon/core: avoid divide-by-zero from pseudo-moving window length calculation

mm/damon/core: avoid divide-by-zero from pseudo-moving window length calculation

When calculating the pseudo-moving access rate, DAMON divides some values
by the maximum nr_accesses.  However, due to the type of the related
variables, simple division-based calculation of the divisor can return
zero.  As a result, divide-by-zero is possible.  Fix it by using
damon_max_nr_accesses(), which handles the case.

Note that this is a fix for a commit that not in the mainline but mm
tree.

Link: https://lkml.kernel.org/r/20231019194924.100347-6-sj@kernel.org
Fixes: ace30fb21af5 ("mm/damon/core: use pseudo-moving sum for nr_accesses_bp")
Reported-by: Jakub Acs <acsjakub@amazon.de>
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>