hugetlb: fix section mismatches

hugetlb_sysfs_add_hstate is called by hugetlb_register_node directly
during init and also indirectly via sysfs after init.

This patch removes the __init tag from hugetlb_sysfs_add_hstate.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>