dev_pm_qos_update_request() can return 1 on success, so don't treat
it as an error.

Fixes: 18c49926 ("cpufreq: Add QoS requests for userspace constraints")
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>