Docs/mm/damon/maintainer-profile: allow posting patches based on damon/next tree

The document mentions any patches for review should based on mm-unstable
instead of damon/next.  It should be the recommended process, but
sometimes patches based on damon/next could be posted for some reasons. 
Actually, the DAMON-based tiered memory management patchset[1] was written
on top of 'young page' DAMOS filter patchset, which was in damon/next tree
as of the writing.

Allow such case and just ask such things to be clearly specified.

[1] https://lore.kernel.org/20240405060858.2818-1-honggyu.kim@sk.com

Link: https://lkml.kernel.org/r/20240503180318.72798-11-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Author: sjp38

Documentation/mm/damon/maintainer-profile.rst

@@ -20,9 +20,10 @@ management subsystem maintainer.  After more sufficient tests, the patches will
 be queued in mm-stable [3]_ , and finally pull-requested to the mainline by the
 memory management subsystem maintainer.
 
-Note again the patches for review should be made against the mm-unstable
-tree [1]_ whenever possible.  damon/next is only for preview of others' works
-in progress.
+Note again the patches for mm-unstable tree [1]_ are queued by the memory
+management subsystem maintainer.  If the patches requires some patches in
+damon/next tree [2]_ which not yet merged in mm-unstable, please make sure the
+requirement is clearly specified.
 
 Submit checklist addendum
 -------------------------