thermal: cpu_cooling: fix return value check in cpufreq_cooling_register()

In case of error, the function thermal_cooling_device_register() returns
ERR_PTR() and never returns NULL. The NULL test in the return value check
should be replaced with IS_ERR().
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>

drivers/thermal/cpu_cooling.c

@@ -469,10 +469,10 @@ cpufreq_cooling_register(const struct cpumask *clip_cpus)
 
 	cool_dev = thermal_cooling_device_register(dev_name, cpufreq_dev,
 						   &cpufreq_cooling_ops);
-	if (!cool_dev) {
+	if (IS_ERR(cool_dev)) {
 		release_idr(&cpufreq_idr, cpufreq_dev->id);
 		kfree(cpufreq_dev);
-		return ERR_PTR(-EINVAL);
+		return cool_dev;
 	}
 	cpufreq_dev->cool_dev = cool_dev;
 	cpufreq_dev->cpufreq_state = 0;