w1: 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.
Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/w1/w1.c

@@ -568,7 +568,7 @@ static struct attribute *w1_master_default_attrs[] = {
 	NULL
 };
 
-static struct attribute_group w1_master_defattr_group = {
+static const struct attribute_group w1_master_defattr_group = {
 	.attrs = w1_master_default_attrs,
 };