libusbhost: Save endpoint ID in usb_request struct

    int actual_length;

    int max_packet_size;

    void *private_data; /* struct usbdevfs_urb* */

    int endpoint;

    void *client_data;  /* free for use by client */

};

                            int length,

                            unsigned int timeout);

/* Reads or writes on a bulk endpoint */

/* Reads or writes on a bulk endpoint.

 * Returns number of bytes transferred, or negative value for error.

 */

int usb_device_bulk_transfer(struct usb_device *device,

                            int endpoint,

                            void* buffer,

    req->dev = dev;

    req->max_packet_size = __le16_to_cpu(ep_desc->wMaxPacketSize);

    req->private_data = urb;

    req->endpoint = urb->endpoint;

    urb->usercontext = req;

    return req;