dt-bindings: ASoC: xlnx, i2s: Document i2s bindings

Added documentation for I2S IP core DT bindings.

Signed-off-by: Maruthi Srinivas Bayyavarapu <maruthi.srinivas.bayyavarapu@xilinx.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
1 file changed