arm: dts: armada: Fix "#cooling-cells" property's name

It should be "#cooling-cells" instead of "cooling-cells". Fix it.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>

arch/arm/boot/dts/armada-385-synology-ds116.dts

@@ -139,7 +139,7 @@ gpio-fan {
 					      3700 5
 					      3900 6
 					      4000 7>;
-			cooling-cells = <2>;
+			#cooling-cells = <2>;
 		};
 
 		gpio-leds {