ARM: dts: berlin2q-marvell-dmp: add missing unit name to /memory node

This patch fixes the following DTC warning with W=1:

"Node /memory has a reg or ranges property, but no unit name"
Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>

arch/arm/boot/dts/berlin2q-marvell-dmp.dts

@@ -43,7 +43,7 @@ / {
 	model = "Marvell BG2-Q DMP";
 	compatible = "marvell,berlin2q-dmp", "marvell,berlin2q", "marvell,berlin";
 
-	memory {
+	memory@0 {
 		device_type = "memory";
 		reg = <0x00000000 0x80000000>;
 	};