mm/damon/core: pass migrate_dests to damos_commit_dests()

mm/damon/core: pass migrate_dests to damos_commit_dests()

damos_commit_dests() receives 'struct damos' pointers, while it uses only
their ->migrate_dests fields.  This makes code unnecessarily difficult to
read.  It also makes unit tests writing complicated.  Refactor the
function to receive pointers to the ->migrate_dests fields.

Link: https://lkml.kernel.org/r/20251111184415.141757-9-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: David Gow <davidgow@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>