[DRIVER][PHY] realtek: Add LED configuration via device tree
Adds initial configuration of the LEDs to the Phy driver via the device tree. Similar to what's done for D18. clea-os/bsp/nxp/linux-seco-imx@8e2cb2a4
- LED_0: Blinks on Activity
- LED_1: Link Speed Indication LED for 100Mbps
- LED_2: Link Speed Indication LED for 1000Mbps