Thanks for replying.
I set "CONFIG_USB_USBNET=y and CONFIG_USB_RTL815=y" but it didn't work on kernel version 4.1
I used configuration file from "http://xenbits.xen.org/people/sstabellini/config-hikey"
I don't know why and I will buy the AX88772 chipset one.
The most weird thing is that the networking is working on kernel version 4.4 running on the flash memory.