usb: gadget: make config_item_type structures const

Make these structures const as they are only passed to the const
argument of the functions config_{group/item}_init_type_name.

Signed-off-by: Bhumika Goyal <bhumirks@gmail.com>
Acked-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

drivers/usb/gadget/function/f_obex.c

@@ -411,7 +411,7 @@ static struct configfs_attribute *acm_attrs[] = {
 	NULL,
 };
 
-static struct config_item_type obex_func_type = {
+static const struct config_item_type obex_func_type = {
 	.ct_item_ops	= &obex_item_ops,
 	.ct_attrs	= acm_attrs,
 	.ct_owner	= THIS_MODULE,