ARM: dts: imx: add cooling-cells for cpufreq cooling device

Add #cooling-cells for i.MX6/7 SoCs for cpufreq cooling device usage.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Signed-off-by: Bastian Stender <bst@pengutronix.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
diff --git a/arch/arm/boot/dts/imx7d.dtsi b/arch/arm/boot/dts/imx7d.dtsi
index 8d3d123..7cbc2ff 100644
--- a/arch/arm/boot/dts/imx7d.dtsi
+++ b/arch/arm/boot/dts/imx7d.dtsi
@@ -11,6 +11,7 @@
 		cpu0: cpu@0 {
 			clock-frequency = <996000000>;
 			operating-points-v2 = <&cpu0_opp_table>;
+			#cooling-cells = <2>;
 		};
 
 		cpu1: cpu@1 {