arm64: dts: mba6ulx: correct GPIO keys wakeup

gpio-keys,wakeup is a deprecated property.

Link: https://lore.kernel.org/r/20230304123341.34223-1-krzysztof.kozlowski@linaro.orgSigned-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

arch/arm/boot/dts/mba6ulx.dtsi

@@ -57,7 +57,7 @@ power-button {
 			label = "POWER";
 			linux,code = <KEY_POWER>;
 			gpios = <&gpio1 3 GPIO_ACTIVE_LOW>;
-			gpio-key,wakeup;
+			wakeup-source;
 		};
 	};