devfreq_cooling: make the structs devfreq_cooling_xxx visible for all

Currently the protection #ifdef CONFIG_DEVFREQ_THERMAL cuts the needed
structures devfreq_cooling_ops and devfreq_cooling_device.
The functions which are supposed to provide the empty implementation complain
about unknown structures.
Similar solution is present in include/linux/devfreq.h.
Reviewed-by: Ørjan Eide <orjan.eide@arm.com>
Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>

include/linux/devfreq_cooling.h

@@ -20,7 +20,6 @@
 #include <linux/devfreq.h>
 #include <linux/thermal.h>
 
-#ifdef CONFIG_DEVFREQ_THERMAL
 
 /**
  * struct devfreq_cooling_power - Devfreq cooling power ops
@@ -43,6 +42,8 @@ struct devfreq_cooling_power {
 	unsigned long dyn_power_coeff;
 };
 
+#ifdef CONFIG_DEVFREQ_THERMAL
+
 struct thermal_cooling_device *
 of_devfreq_cooling_register_power(struct device_node *np, struct devfreq *df,
 				  struct devfreq_cooling_power *dfc_power);