net: phy: realtek: add support for RTL8365MB-VC internal PHYs

The RTL8365MB-VC ethernet switch controller has 4 internal PHYs for its
user-facing ports. All that is needed is to let the PHY driver core
pick up the IRQ made available by the switch driver.

Signed-off-by: Alvin Šipraga <alsi@bang-olufsen.dk>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>