misc: isl29020: 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/misc/isl29020.c

@@ -145,7 +145,7 @@ static struct attribute *mid_att_als[] = {
 	NULL
 };
 
-static struct attribute_group m_als_gr = {
+static const struct attribute_group m_als_gr = {
 	.name = "isl29020",
 	.attrs = mid_att_als
 };