mm, mem-hotplug: fix section mismatch. setup_per_zone_inactive_ratio() should be __meminit.

Commit bce7394a ("page-allocator: reset wmark_min and inactive ratio of
zone when hotplug happens") introduced invalid section references.  Now,
setup_per_zone_inactive_ratio() is marked __init and then it can't be
referenced from memory hotplug code.

This patch marks it as __meminit and also marks caller as __ref.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>