cpuidle: Call cpu_latency_qos_limit() instead of pm_qos_request()

Call cpu_latency_qos_limit() instead of pm_qos_request(), because the
latter is going to be dropped.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Amit Kucheria <amit.kucheria@linaro.org>
Tested-by: Amit Kucheria <amit.kucheria@linaro.org>