mm/page_alloc.c: use '__paginginit' instead of '__init'

set_pageblock_order() may be called when memory hotplug, so need use
'__paginginit' instead of '__init'.

The related warning:

  The function __meminit .free_area_init_node() references
  a function __init .set_pageblock_order().
  If .set_pageblock_order is only used by .free_area_init_node then
  annotate .set_pageblock_order with a matching annotation.

Change-Id: I982ee702a2ff92670cf386cabcc47fdfd3de8180
Signed-off-by: Chen Gang <gang.chen@asianux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Git-commit: 15ca220e1a63af06e000691e4ae1beaba5430c32
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Signed-off-by: Laura Abbott <lauraa@codeaurora.org>