arm64: dts: berlin4ct: add missing unit name to /soc node

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

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

arch/arm64/boot/dts/marvell/berlin4ct.dtsi

@@ -142,7 +142,7 @@ timer {
 			     <GIC_PPI 10 (GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_LOW)>;
 	};
 
-	soc {
+	soc@f7000000 {
 		compatible = "simple-bus";
 		#address-cells = <1>;
 		#size-cells = <1>;