Revert "drivers: base: power: wakeup.c: Use built-in RCU list checking"

This reverts commit 8ba88804

 as a better
version is already in Rafael's tree, sorry about that.

Reported-by: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>