Removed the following sparse warnings:
*  mm/hugetlb.c:1764:6: warning: symbol
    'hugetlb_unregister_node' was not declared.
    Should it be static?
*   mm/hugetlb.c:1808:6: warning: symbol
    'hugetlb_register_node' was not declared.
    Should it be static?
Signed-off-by: NClaudiu Ghioc <claudiu.ghioc@gmail.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>