mm/hugetlb.c: constify attribute_group structures

attribute_group are not supposed to change at runtime.  All functions
working with attribute_group provided by <linux/sysfs.h> work with const
attribute_group.  So mark the non-const structs as const.

Link: http://lkml.kernel.org/r/1501157260-3922-1-git-send-email-arvind.yadav.cs@gmail.comSigned-off-by: NArvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mm/hugetlb.c

@@ -2569,13 +2569,13 @@ static struct attribute *hstate_attrs[] = {
 	NULL,
 };
 
-static struct attribute_group hstate_attr_group = {
+static const struct attribute_group hstate_attr_group = {
 	.attrs = hstate_attrs,
 };
 
 static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent,
 				    struct kobject **hstate_kobjs,
-				    struct attribute_group *hstate_attr_group)
+				    const struct attribute_group *hstate_attr_group)
 {
 	int retval;
 	int hi = hstate_index(h);
@@ -2633,7 +2633,7 @@ static struct attribute *per_node_hstate_attrs[] = {
 	NULL,
 };
 
-static struct attribute_group per_node_hstate_attr_group = {
+static const struct attribute_group per_node_hstate_attr_group = {
 	.attrs = per_node_hstate_attrs,
 };