arm64: dts: amlogic: a1: add cooling-cells for DVFS feature

It's used for CPU with DVFS feature to specify minimum and maximum
cooling state used in the reference.
Without these values DVFS will not work and dtbs_check will raise the
error.

Signed-off-by: Dmitry Rokosov <ddrokosov@salutedevices.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20240328192645.20914-2-ddrokosov@salutedevices.com
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>

arch/arm64/boot/dts/amlogic/meson-a1.dtsi

@@ -28,6 +28,7 @@
 			reg = <0x0 0x0>;
 			enable-method = "psci";
 			next-level-cache = <&l2>;
+			#cooling-cells = <2>;
 		};
 
 		cpu1: cpu@1 {
@@ -36,6 +37,7 @@
 			reg = <0x0 0x1>;
 			enable-method = "psci";
 			next-level-cache = <&l2>;
+			#cooling-cells = <2>;
 		};
 
 		l2: l2-cache0 {