PM / QoS: Add pm_qos_update_target/flags tracepoints

This patch adds tracepoints to pm_qos_update_target and
pm_qos_update_flags. It's useful for checking pm qos action,
previous value and current value.

Signed-off-by: Sahara <keun-o.park@windriver.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>