struct usb_gadget_strings — a set of USB strings in a given language
struct usb_gadget_strings {
  u16 language;
  struct usb_string * strings;
};  identifies the strings' language (0x0409 for en-us)
array of strings with their ids
   If you're using usb_gadget_get_string, use this to wrap all the
   strings for a given language.