ARM: mvebu: Conform L2CC node with ePAPR specification by adding cache-level

For L2 cache controller node, cache-level property is mandatory. Let's
add it to Armada 370 and Armada XP device tree.

Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Reviewed-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
diff --git a/arch/arm/boot/dts/armada-370.dtsi b/arch/arm/boot/dts/armada-370.dtsi
index 50f259b..00b50db5 100644
--- a/arch/arm/boot/dts/armada-370.dtsi
+++ b/arch/arm/boot/dts/armada-370.dtsi
@@ -129,6 +129,7 @@
 				compatible = "marvell,aurora-outer-cache";
 				reg = <0x08000 0x1000>;
 				cache-id-part = <0x100>;
+				cache-level = <2>;
 				cache-unified;
 				wt-override;
 			};
diff --git a/arch/arm/boot/dts/armada-xp.dtsi b/arch/arm/boot/dts/armada-xp.dtsi
index 448af33..013d63f 100644
--- a/arch/arm/boot/dts/armada-xp.dtsi
+++ b/arch/arm/boot/dts/armada-xp.dtsi
@@ -79,6 +79,7 @@
 				compatible = "marvell,aurora-system-cache";
 				reg = <0x08000 0x1000>;
 				cache-id-part = <0x100>;
+				cache-level = <2>;
 				cache-unified;
 				wt-override;
 			};