ath79: add missing clock name strings in SoC dtsi

For all SoC in the ath79 target, the PLL controller provides 3 main
clocks "cpu", "ddr" and "ahb" through the input clock "ref".

Signed-off-by: Shiji Yang <yangshiji66@qq.com>

target/linux/ath79/dts/ar9330.dtsi

@@ -28,6 +28,12 @@
 		bootargs = "console=ttyATH0,115200";
 	};
 
+	ref: ref {
+		compatible = "fixed-clock";
+		#clock-cells = <0>;
+		clock-output-names = "ref";
+	};
+
 	ahb {
 		apb {
 			ddr_ctrl: memory-controller@18000000 {
@@ -83,7 +89,11 @@
 				compatible = "qca,ar9330-pll";
 				reg = <0x18050000 0x100>;
 
+				clocks = <&ref>;
+				clock-names = "ref";
+
 				#clock-cells = <1>;
+				clock-output-names = "cpu", "ddr", "ahb";
 			};
 
 			wdt: wdt@18060008 {

target/linux/ath79/dts/ar9331.dtsi

@@ -4,9 +4,4 @@
 
 / {
 	compatible = "qca,ar9331";
-
-	ref: ref {
-		compatible = "fixed-clock";
-		#clock-cells = <0>;
-	};
 };

target/linux/ath79/dts/qca953x.dtsi

@@ -104,7 +104,9 @@
 
 				#clock-cells = <1>;
 				clock-output-names = "cpu", "ddr", "ahb";
+
 				clocks = <&extosc>;
+				clock-names = "ref";
 			};
 
 			wdt: wdt@18060008 {

target/linux/ath79/dts/qca955x.dtsi

@@ -119,6 +119,7 @@
 				clock-output-names = "cpu", "ddr", "ahb";
 
 				clocks = <&extosc>;
+				clock-names = "ref";
 			};
 
 			wdt: wdt@18060008 {

target/linux/ath79/dts/qca956x.dtsi

@@ -95,6 +95,7 @@
 				clock-output-names = "cpu", "ddr", "ahb";
 
 				clocks = <&extosc>;
+				clock-names = "ref";
 			};
 
 			wdt: wdt@18060008 {