ARM: Kirkwood: DT: Add missing #sound-dai-cells property

The sound node is missing a #sound-dai-cells property. Add it, so that
the sounds node can be used in combination with the simple-audio-card
binding.
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lkml.kernel.org/r/1399141819-23924-5-git-send-email-andrew@lunn.chSigned-off-by: Jason Cooper <jason@lakedaemon.net>

arch/arm/boot/dts/kirkwood.dtsi

@@ -372,6 +372,7 @@ sata_phy1: sata-phy@84000 {
 
 		audio0: audio-controller@a0000 {
 			compatible = "marvell,kirkwood-audio";
+			#sound-dai-cells = <0>;
 			reg = <0xa0000 0x2210>;
 			interrupts = <24>;
 			clocks = <&gate_clk 9>;