ARM: dts: uniphier: add reference clock nodes

Add master clock nodes generated by crystal oscillators.

  PH1-sLD3, PH1-LD4: 24.576 MHz
  PH1-Pro4, ProXstream2: 25.000 MHz
  PH1-Pro5: 20.000 MHz

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/arch/arm/dts/uniphier-common32.dtsi b/arch/arm/dts/uniphier-common32.dtsi
index 5d4b2cf..de04de1 100644
--- a/arch/arm/dts/uniphier-common32.dtsi
+++ b/arch/arm/dts/uniphier-common32.dtsi
@@ -9,6 +9,13 @@
 /include/ "skeleton.dtsi"
 
 / {
+	clocks {
+		refclk: ref {
+			#clock-cells = <0>;
+			compatible = "fixed-clock";
+		};
+	};
+
 	soc: soc {
 		compatible = "simple-bus";
 		#address-cells = <1>;