arm64: dts: marvell: armada-ap806: reserve PSCI area

The memory area [0x4000000-0x4200000[ is occupied by the PSCI firmware. Any
attempt to access it from U-Boot leads to an immediate crash.

So let's make the same memory reservation as the vendor device tree.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Stefan Roese <sr@denx.de>
diff --git a/arch/arm/dts/armada-ap806.dtsi b/arch/arm/dts/armada-ap806.dtsi
index ebdee51..713c2db 100644
--- a/arch/arm/dts/armada-ap806.dtsi
+++ b/arch/arm/dts/armada-ap806.dtsi
@@ -64,6 +64,17 @@
 		method = "smc";
 	};
 
+	reserved-memory {
+		#address-cells = <2>;
+		#size-cells = <2>;
+		ranges;
+
+		psci-area@4000000 {
+			reg = <0x0 0x4000000 0x0 0x200000>;
+			no-map;
+		};
+	};
+
 	ap806 {
 		#address-cells = <2>;
 		#size-cells = <2>;