powercap: dtpm_cpu: Fix error check against freq_qos_add_request()

The caller of the function freq_qos_add_request() checks again a non
zero value but freq_qos_add_request() can return '1' if the request
already exists. Therefore, the setup function fails while the QoS
request actually did not failed.

Fix that by changing the check against a negative value like all the
other callers of the function.

Fixes: 0e8f68d ("Add CPU energy model based support")
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Author: dlezcano

drivers/powercap/dtpm_cpu.c

@@ -219,7 +219,7 @@ static int __dtpm_cpu_setup(int cpu, struct dtpm *parent)
 	ret = freq_qos_add_request(&policy->constraints,
 				   &dtpm_cpu->qos_req, FREQ_QOS_MAX,
 				   pd->table[pd->nr_perf_states - 1].frequency);
-	if (ret)
+	if (ret < 0)
 		goto out_dtpm_unregister;
 
 	cpufreq_cpu_put(policy);