mm/damon/sysfs-schemes: remove outdated TODO in target_nid_store()

mm/damon/sysfs-schemes: remove outdated TODO in target_nid_store()

The TODO comment in target_nid_store() suggested adding range validation
for target_nid.  As discussed in [1], the current behavior of accepting
any integer value is intentional.  DAMON sysfs aims to remain flexible,
including supporting users who prepare node IDs before future NUMA hotplug
events.

Because this behavior matches the broader design philosophy of the DAMON
sysfs interface, the TODO comment is now misleading.  This patch removes
the comment without introducing any behavioral change.

No functional changes.

Link: https://lkml.kernel.org/r/20251211032722.4928-2-swarajgaikwad1925@gmail.com
Link: https://lore.kernel.org/lkml/20251210150930.57679-1-sj@kernel.org/
Signed-off-by: Swaraj Gaikwad <swarajgaikwad1925@gmail.com>
Suggested-by: SeongJae Park <sj@kernel.org>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>