ASoC: rt5514: Add devicetree binding support for rt5514-spi

Add devicetree binding support for rt5514 spi dsp codec.
Signed-off-by: Jeffy Chen <jeffy.chen@rock-chips.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/sound/rt5514.txt

 RT5514 audio CODEC
 
-This device supports I2C only.
+This device supports both I2C and SPI.
 
 Required properties:
 
 - compatible : "realtek,rt5514".
 
-- reg : The I2C address of the device.
+- reg : the I2C address of the device for I2C, the chip select
+        number for SPI.
 
 Optional properties:
 
 - clocks: The phandle of the master clock to the CODEC
 - clock-names: Should be "mclk"
 
+- interrupt-parent: The phandle for the interrupt controller.
+- interrupts: The interrupt number to the cpu. The interrupt specifier format
+	      depends on the interrupt controller.
+
 - realtek,dmic-init-delay-ms
-  Set the DMIC initial delay (ms) to wait it ready.
+  Set the DMIC initial delay (ms) to wait it ready for I2C.
 
-Pins on the device (for linking into audio routes) for RT5514:
+Pins on the device (for linking into audio routes) for I2C:
 
   * DMIC1L
   * DMIC1R