net: phy: aquantia: add AQR813 PHY ID

Aquantia AQR813 is the Octal Port variant of the AQR113. Add PHY ID for
it to provide support for it.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>