The default mode for the ADAU1761 on the ZedBoard is I2C rather than SPI and all of the drivers and code I have seen use that mode.
From a quick look at the data sheet (available here: http://www.analog.com/media/en/technical-documentation/data-sheets/ADAU1761.pdf ) it appears that the device does not have an SPI 'address' but is 'enabled' by asserting the 'CLATCH' signal. You can take a look at the ZedBoard schematic to determine the Zynq FPGA connections to the ADU1761 control signals. The ZedBoard schematic can be found here:
I did find one tutorial for the ZedBoard that implements an SPI interface to the ADU1761 on the ZedBoard. I have not tried this tutorial so I don't know how useful it will be:
