ARM: dts: ux500: Fix up the CPU thermal zone

This fixes up the default ux500 CPU thermal zone:

- Set polling delay to 0 and explain why
- Set passive polling delay to 250
- Remove restrictions from the CPU cooling device,
  we should use all cpufreq steps to cool down if
  needed.

Link: https://lore.kernel.org/r/20191001074628.8122-1-linus.walleij@linaro.org
Fixes: b786a05f6c ("ARM: dts: ux500: Update thermal zone")
Suggested-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Olof Johansson <olof@lixom.net>

arch/arm/boot/dts/ste-dbx5x0.dtsi

@@ -8,6 +8,7 @@
 #include <dt-bindings/mfd/dbx500-prcmu.h>
 #include <dt-bindings/arm/ux500_pm_domains.h>
 #include <dt-bindings/gpio/gpio.h>
+#include <dt-bindings/thermal/thermal.h>
 
 / {
 	#address-cells = <1>;
@@ -59,8 +60,12 @@
 		 * cooling.
 		 */
 		cpu_thermal: cpu-thermal {
-			polling-delay-passive = <0>;
-			polling-delay = <1000>;
+			polling-delay-passive = <250>;
+			/*
+			 * This sensor fires interrupts to update the thermal
+			 * zone, so no polling is needed.
+			 */
+			polling-delay = <0>;
 
 			thermal-sensors = <&thermal>;
 
@@ -79,7 +84,7 @@
 
 			cooling-maps {
 				trip = <&cpu_alert>;
-				cooling-device = <&CPU0 0 2>;
+				cooling-device = <&CPU0 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
 				contribution = <100>;
 			};
 		};