subsys: usb: validate and update endpoint address

Add the routine to validate endpoint address and update the endpoint
descriptors and usb_ep_cfg_data at runtime.

Signed-off-by: Johann Fischer <j.fischer@phytec.de>

include/usb/usb_device.h

@@ -167,6 +167,8 @@ struct usb_cfg_data {
 	 * http://www.beyondlogic.org/usbnutshell/usb5.shtml#DeviceDescriptors
 	 */
 	const u8_t *usb_device_description;
+	/** Pointer to interface descriptor */
+	const void *interface_descriptor;
 	/** Callback to be notified on USB connection status change */
 	usb_status_callback cb_usb_status;
 	/** USB interface (Class) handler and storage space */