Add the RTL8231 controlling the port LEDs to the devicetree, so users
can enable them. Using the appropriate link name, the netdev trigger can
be used to reflect the port status. As no hardware port status
offloading is supported, blinking on traffic could result in increased
load due to the numerous LED updates.
Signed-off-by: Sander Vanheule <sander@svanheule.net>