linux-imx

PM / wakeup: add a dummy wakeup_source to record statistics

After a wakeup_source is destroyed, we lost all information such as how
long this wakeup_source has been active. Add a dummy wakeup_source to
record such info.

Signed-off-by: Jin Qian <jinqian@android.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>