Micrel KS8851 Ethernet mac (MLL)

Required properties:
- compatible = "micrel,ks8851-mll" of parallel interface
- reg : 2 physical address and size of registers for data and command
- interrupts : interrupt connection

Micrel KS8851 Ethernet mac (SPI)

Required properties:
- compatible = "micrel,ks8851" or the deprecated "ks8851"
- reg : chip select number
- interrupts : interrupt connection

Optional properties:
- vdd-supply: analog 3.3V supply for Ethernet mac
- vdd-io-supply: digital 1.8V IO supply for Ethernet mac
- reset-gpios: reset_n input pin