ARM: dts: en7523: add missing cache properties

As all level 2 and level 3 caches are unified, add required
cache-unified and cache-level properties to fix warnings like:

  en7523-evb.dtb: l2-cache0: 'cache-level' is a required property
  en7523-evb.dtb: l2-cache0: 'cache-unified' is a required property
Reviewed-by: Alexandre Mergnat <amergnat@baylibre.com>
Link: https://lore.kernel.org/r/20230423150824.118430-1-krzysztof.kozlowski@linaro.orgSigned-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

arch/arm/boot/dts/en7523.dtsi

@@ -81,6 +81,8 @@ cpu1: cpu@1 {
 
 		L2_0: l2-cache0 {
 			compatible = "cache";
+			cache-level = <2>;
+			cache-unified;
 		};
 	};