mm: fix kerneldoc on mem_cgroup_replace_page

Whoops, I missed removing the kerneldoc comment of the lrucare arg
removed from mem_cgroup_replace_page; but it's a good comment, keep it.

Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>