arm64: dts: amazon: add missing cache properties

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

  alpine-v3-evp.dtb: cache@0: 'cache-unified' is a dependency of 'cache-size'

Link: https://lore.kernel.org/r/20230421223141.115072-1-krzysztof.kozlowski@linaro.orgSigned-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

arch/arm64/boot/dts/amazon/alpine-v3.dtsi

@@ -250,6 +250,7 @@ cluster0_l2: cache@0 {
 			cache-line-size = <64>;
 			cache-sets = <2048>;
 			cache-level = <2>;
+			cache-unified;
 		};
 
 		cluster1_l2: cache@100 {
@@ -258,6 +259,7 @@ cluster1_l2: cache@100 {
 			cache-line-size = <64>;
 			cache-sets = <2048>;
 			cache-level = <2>;
+			cache-unified;
 		};
 
 		cluster2_l2: cache@200 {
@@ -266,6 +268,7 @@ cluster2_l2: cache@200 {
 			cache-line-size = <64>;
 			cache-sets = <2048>;
 			cache-level = <2>;
+			cache-unified;
 		};
 
 		cluster3_l2: cache@300 {
@@ -274,6 +277,7 @@ cluster3_l2: cache@300 {
 			cache-line-size = <64>;
 			cache-sets = <2048>;
 			cache-level = <2>;
+			cache-unified;
 		};
 
 	};