thermal: gov_power_allocator: Refactor check_power_actors()

In preparation for a subsequent change, rearrange check_power_actors().

No intentional functional impact.
Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/thermal/gov_power_allocator.c

@@ -581,8 +581,9 @@ static void allow_maximum_power(struct thermal_zone_device *tz, bool update)
  * power actor API. The warning should help to investigate the issue, which
  * could be e.g. lack of Energy Model for a given device.
  *
- * Return: 0 on success, -EINVAL if any cooling device does not implement
- * the power actor API.
+ * If all of the cooling devices currently attached to @tz implement the power
+ * actor API, return the number of them (which may be 0, because some cooling
+ * devices may be attached later). Otherwise, return -EINVAL.
  */
 static int check_power_actors(struct thermal_zone_device *tz,
 			      struct power_allocator_params *params)
@@ -597,8 +598,9 @@ static int check_power_actors(struct thermal_zone_device *tz,
 		if (!cdev_is_power_actor(instance->cdev)) {
 			dev_warn(&tz->device, "power_allocator: %s is not a power actor\n",
 				 instance->cdev->type);
-			ret = -EINVAL;
+			return -EINVAL;
 		}
+		ret++;
 	}
 
 	return ret;
@@ -631,7 +633,7 @@ static int power_allocator_bind(struct thermal_zone_device *tz)
 	}
 
 	ret = check_power_actors(tz, params);
-	if (ret) {
+	if (ret < 0) {
 		dev_warn(&tz->device, "power_allocator: binding failed\n");
 		kfree(params);
 		return ret;