arm64: dts: Add L2-cache DT node for NS2

Recent kernels requires cache hierrachy to be defined via DT hence
this patch updates NS2 DT accordingly.
Signed-off-by: Anup Patel <anup.patel@broadcom.com>
Reviewed-by: Sandeep Tripathy <tripathy@broadcom.com>
Reviewed-by: Ray Jui <rjui@broadcom.com>
Reviewed-by: Scott Branden <sbranden@broadcom.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>

arch/arm64/boot/dts/broadcom/ns2.dtsi

@@ -50,6 +50,7 @@ cpu@0 {
 			reg = <0 0>;
 			enable-method = "spin-table";
 			cpu-release-addr = <0 0x84b00000>;
+			next-level-cache = <&CLUSTER0_L2>;
 		};
 
 		cpu@1 {
@@ -58,6 +59,7 @@ cpu@1 {
 			reg = <0 1>;
 			enable-method = "spin-table";
 			cpu-release-addr = <0 0x84b00000>;
+			next-level-cache = <&CLUSTER0_L2>;
 		};
 
 		cpu@2 {
@@ -66,6 +68,7 @@ cpu@2 {
 			reg = <0 2>;
 			enable-method = "spin-table";
 			cpu-release-addr = <0 0x84b00000>;
+			next-level-cache = <&CLUSTER0_L2>;
 		};
 
 		cpu@3 {
@@ -74,6 +77,11 @@ cpu@3 {
 			reg = <0 3>;
 			enable-method = "spin-table";
 			cpu-release-addr = <0 0x84b00000>;
+			next-level-cache = <&CLUSTER0_L2>;
+		};
+
+		CLUSTER0_L2: l2-cache@000 {
+			compatible = "cache";
 		};
 	};