ARM64: zynqmp: Remove DTC 1.4.2 warnings

DTC 1.4.2 reports these warnings:
Warning (unit_address_vs_reg): Node /amba_apu has a reg or ranges
property, but no unit name
Warning (unit_address_vs_reg): Node /amba has a reg or ranges property,
but no unit name
Warning (unit_address_vs_reg): Node /amba/usb@fe200000 has a unit name,
but no reg property
Warning (unit_address_vs_reg): Node /amba/usb@fe300000 has a unit name,
but no reg property
Warning (unit_address_vs_reg): Node
/amba/dma@fd4c0000/dma-video0channel@fd4c0000 has a unit name, but no
reg property
Warning (unit_address_vs_reg): Node
/amba/dma@fd4c0000/dma-video1channel@fd4c0000 has a unit name, but no
reg property
Warning (unit_address_vs_reg): Node
/amba/dma@fd4c0000/dma-video2channel@fd4c0000 has a unit name, but no
reg property
Warning (unit_address_vs_reg): Node
/amba/dma@fd4c0000/dma-graphicschannel@fd4c0000 has a unit name, but no
reg property
Warning (unit_address_vs_reg): Node
/amba/dma@fd4c0000/dma-audio0channel@fd4c0000 has a unit name, but no
reg property
Warning (unit_address_vs_reg): Node
/amba/dma@fd4c0000/dma-audio1channel@fd4c0000 has a unit name, but no
reg property
Warning (unit_address_vs_reg): Node /memory has a reg or ranges
property, but no unit name

This patch is fixing them.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/arch/arm/dts/zynqmp-ep108.dts b/arch/arm/dts/zynqmp-ep108.dts
index 0bbf9a7..7517170 100644
--- a/arch/arm/dts/zynqmp-ep108.dts
+++ b/arch/arm/dts/zynqmp-ep108.dts
@@ -31,7 +31,7 @@
 		stdout-path = "serial0:115200n8";
 	};
 
-	memory {
+	memory@0 {
 		device_type = "memory";
 		reg = <0x0 0x0 0x0 0x40000000>;
 	};