net: dsa: realtek: rtl8365mb: add RTL8367RB-VB support

RTL8367RB-VB is a 5+2 port 10/100/1000M Ethernet switch.
It is similar to RTL8367S but in this version, both
external interfaces are RGMII.

Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>