usb: chipidea: 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/chipidea/core.c

@@ -887,7 +887,7 @@ static struct attribute *ci_attrs[] = {
 	NULL,
 };
 
-static struct attribute_group ci_attr_group = {
+static const struct attribute_group ci_attr_group = {
 	.attrs = ci_attrs,
 };