Docs/mm/damon/design: fix wrong link to intervals goal section

Docs/mm/damon/design: fix wrong link to intervals goal section

Commit b243d666d107 ("Docs/admin-guide/mm/damon/usage: add intervals_goal
directory on the hierarchy") mistakenly added a wrong reference for
intervals goal usage documentation on the design document.  Fix it.

Link: https://lkml.kernel.org/r/20251026182216.118200-3-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>