arm64: dts: fvp: Move fixed clocks out of bus node

The devicetree compiler complains when DT nodes without a reg property
live inside a (simple) bus node:
Warning (simple_bus_reg): Node /bus@8000000/v2m_refclk32khz
                          missing or empty reg/ranges property

Move the fixed clocks to the root node, since they do not depend on any
busses.

Link: https://lore.kernel.org/r/20200513103016.130417-6-andre.przywara@arm.com
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

arch/arm64/boot/dts/arm/foundation-v8.dtsi

@@ -92,6 +92,27 @@
 		timeout-sec = <30>;
 	};
 
+	v2m_clk24mhz: clk24mhz {
+		compatible = "fixed-clock";
+		#clock-cells = <0>;
+		clock-frequency = <24000000>;
+		clock-output-names = "v2m:clk24mhz";
+	};
+
+	v2m_refclk1mhz: refclk1mhz {
+		compatible = "fixed-clock";
+		#clock-cells = <0>;
+		clock-frequency = <1000000>;
+		clock-output-names = "v2m:refclk1mhz";
+	};
+
+	v2m_refclk32khz: refclk32khz {
+		compatible = "fixed-clock";
+		#clock-cells = <0>;
+		clock-frequency = <32768>;
+		clock-output-names = "v2m:refclk32khz";
+	};
+
 	bus@8000000 {
 		compatible = "arm,vexpress,v2m-p1", "simple-bus";
 		arm,v2m-memory-map = "rs1";
@@ -157,27 +178,6 @@
 			interrupts = <15>;
 		};
 
-		v2m_clk24mhz: clk24mhz {
-			compatible = "fixed-clock";
-			#clock-cells = <0>;
-			clock-frequency = <24000000>;
-			clock-output-names = "v2m:clk24mhz";
-		};
-
-		v2m_refclk1mhz: refclk1mhz {
-			compatible = "fixed-clock";
-			#clock-cells = <0>;
-			clock-frequency = <1000000>;
-			clock-output-names = "v2m:refclk1mhz";
-		};
-
-		v2m_refclk32khz: refclk32khz {
-			compatible = "fixed-clock";
-			#clock-cells = <0>;
-			clock-frequency = <32768>;
-			clock-output-names = "v2m:refclk32khz";
-		};
-
 		iofpga@300000000 {
 			compatible = "simple-bus";
 			#address-cells = <1>;