sound: rockchip: Add sound support for jerry

Jerry uses a max98090 audio codec and the internal SoC I2S peripheral.
Enable sound support and add the required device-tree pieces.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
diff --git a/arch/arm/dts/rk3288.dtsi b/arch/arm/dts/rk3288.dtsi
index 273d38c..487d22c 100644
--- a/arch/arm/dts/rk3288.dtsi
+++ b/arch/arm/dts/rk3288.dtsi
@@ -649,6 +649,7 @@
 		interrupts = <GIC_SPI 85 IRQ_TYPE_LEVEL_HIGH>;
 		#address-cells = <1>;
 		#size-cells = <0>;
+		#sound-dai-cells = <1>;
 		dmas = <&dmac_bus_s 0>, <&dmac_bus_s 1>;
 		dma-names = "tx", "rx";
 		clock-names = "i2s_hclk", "i2s_clk";