ARM: dts: am4372: Add missing unit name to memory nodes

This patch fixes the following DTC warnings:

"Node /memory has a reg or ranges property, but no unit name"
Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/boot/dts/am4372.dtsi

@@ -17,7 +17,7 @@ / {
 	#address-cells = <1>;
 	#size-cells = <1>;
 
-	memory {
+	memory@0 {
 		device_type = "memory";
 		reg = <0 0>;
 	};