ARM64: zynqmp: Fix W=1 dtc 1.4 warnings

The patch removes these warnings reported by dtc 1.4:
Warning (unit_address_vs_reg): Node /amba_apu has a reg or ranges
property, but no unit name
Warning (unit_address_vs_reg): Node /memory has a reg or ranges
property, but no unit name
Signed-off-by: Michal Simek <michal.simek@xilinx.com>

arch/arm64/boot/dts/xilinx/zynqmp-ep108.dts

@@ -27,7 +27,7 @@ chosen {
 		stdout-path = "serial0:115200n8";
 	};
 
-	memory {
+	memory@0 {
 		device_type = "memory";
 		reg = <0x0 0x0 0x0 0x40000000>;
 	};

arch/arm64/boot/dts/xilinx/zynqmp.dtsi

@@ -72,7 +72,7 @@ timer {
 			     <1 10 0xf08>;
 	};
 
-	amba_apu {
+	amba_apu: amba_apu@0 {
 		compatible = "simple-bus";
 		#address-cells = <2>;
 		#size-cells = <1>;