drivers: mmc: Call cpu_latency_qos_*() instead of pm_qos_*()

Call cpu_latency_qos_add/remove_request() instead of
pm_qos_add/remove_request(), respectively, because the
latter are 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>