mm/damon: add a kernel-doc comment for damon_ctx->probes

mm/damon: add a kernel-doc comment for damon_ctx->probes

The two fields of damon_ctx struct dont have their kernel-doc comments.
That causes kernel document builds to warn.  Fix those.

This patch (of 2):

Fix below document build warning:

    WARNING: ../include/linux/damon.h:909 struct member 'probes' not described in 'damon_ctx'

Link: https://lore.kernel.org/20260628220808.98931-1-sj@kernel.org
Link: https://lore.kernel.org/20260628220808.98931-2-sj@kernel.org
Fixes: 18c777859f28 ("mm/damon/core: embed damon_probe objects in damon_ctx")
Signed-off-by: SJ Park <sj@kernel.org>
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Closes: https://lore.kernel.org/4df95955-b255-4e5a-90c4-35db02f3111f@infradead.org
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>