ARM: dts: uniphier: add syscon property for UniPhier sound system

This patch adds syscon property for specifying soc-glue core into
device-tree of PXs2 SoC.

Currently, soc-glue core is used for changing the state of S/PDIF
signal output pin to signal output state or Hi-Z state.
Signed-off-by: Katsuhiro Suzuki <suzuki.katsuhiro@socionext.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

arch/arm/boot/dts/uniphier-pxs2.dtsi

@@ -242,6 +242,7 @@ audio@56000000 {
 			reset-names = "aio";
 			resets = <&sys_rst 40>;
 			#sound-dai-cells = <1>;
+			socionext,syscon = <&soc_glue>;
 
 			i2s_port0: port@0 {
 				i2s_hdmi: endpoint {
@@ -418,7 +419,7 @@ peri_rst: reset {
 			};
 		};
 
-		soc-glue@5f800000 {
+		soc_glue: soc-glue@5f800000 {
 			compatible = "socionext,uniphier-pxs2-soc-glue",
 				     "simple-mfd", "syscon";
 			reg = <0x5f800000 0x2000>;