ARM: dts: s3c6410: move fixed clocks under root node in SMDK6410

The fixed clocks are kept under dedicated 'clocks' node but this causes
multiple dtschema warnings:

  clocks: $nodename:0: 'clocks' does not match '^([a-z][a-z0-9\\-]+-bus|bus|soc|axi|ahb|apb)(@[0-9a-f]+)?$'
  clocks: #size-cells:0:0: 0 is not one of [1, 2]
  clocks: oscillator@0:reg:0: [0] is too short
  clocks: oscillator@1:reg:0: [1] is too short
  clocks: 'ranges' is a required property
  oscillator@0: 'reg' does not match any of the regexes: 'pinctrl-[0-9]+'
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Link: https://lore.kernel.org/r/20200907183313.29234-4-krzk@kernel.org

arch/arm/boot/dts/s3c6410-smdk6410.dts

@@ -28,26 +28,18 @@ chosen {
 		bootargs = "console=ttySAC0,115200n8 earlyprintk rootwait root=/dev/mmcblk0p1";
 	};
 
-	clocks {
-		compatible = "simple-bus";
-		#address-cells = <1>;
-		#size-cells = <0>;
-
-		fin_pll: oscillator@0 {
-			compatible = "fixed-clock";
-			reg = <0>;
-			clock-frequency = <12000000>;
-			clock-output-names = "fin_pll";
-			#clock-cells = <0>;
-		};
+	fin_pll: oscillator-0 {
+		compatible = "fixed-clock";
+		clock-frequency = <12000000>;
+		clock-output-names = "fin_pll";
+		#clock-cells = <0>;
+	};
 
-		xusbxti: oscillator@1 {
-			compatible = "fixed-clock";
-			reg = <1>;
-			clock-output-names = "xusbxti";
-			clock-frequency = <48000000>;
-			#clock-cells = <0>;
-		};
+	xusbxti: oscillator-1 {
+		compatible = "fixed-clock";
+		clock-output-names = "xusbxti";
+		clock-frequency = <48000000>;
+		#clock-cells = <0>;
 	};
 
 	srom-cs1@18000000 {