usb: usbsevseg: 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/usb/misc/usbsevseg.c

@@ -330,7 +330,7 @@ static struct attribute *dev_attrs[] = {
 	NULL
 };
 
-static struct attribute_group dev_attr_grp = {
+static const struct attribute_group dev_attr_grp = {
 	.attrs = dev_attrs,
 };