hugetlb: fix sparse warning for hugetlb_register_node

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: Claudiu Ghioc <claudiu.ghioc@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 4f3ea0b..b336690 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1763,7 +1763,7 @@
  * Unregister hstate attributes from a single node device.
  * No-op if no hstate attributes attached.
  */
-void hugetlb_unregister_node(struct node *node)
+static void hugetlb_unregister_node(struct node *node)
 {
 	struct hstate *h;
 	struct node_hstate *nhs = &node_hstates[node->dev.id];
@@ -1807,7 +1807,7 @@
  * Register hstate attributes for a single node device.
  * No-op if attributes already registered.
  */
-void hugetlb_register_node(struct node *node)
+static void hugetlb_register_node(struct node *node)
 {
 	struct hstate *h;
 	struct node_hstate *nhs = &node_hstates[node->dev.id];