dts-binding doc for opencores

[Thomas Chou]

Hi Jonas,

As Grant suggested, we will need to document the dts property for 
opencores drivers. Do you have any suggestion?

linux-2.6/Documentation/powerpc/dts-bindings/opencores.txt

project: tiny SPI controller
core: tiny_spi
driver: spi_oc_tiny
compat: "opencores,tiny-spi-rtlsvn2"
Optional properties:
        - clock-frequency : input clock freq to the core
        - baud-width: baud rate divider width of the core

Best regards,
Thomas