Freezer / cgroup freezer: Update stale locking comments
Update stale comments regarding locking order and add a little more detail
so it's easier to follow the locking between the cgroup freezer and the
power management freezer code.
Signed-off-by: Matt Helsley <firstname.lastname@example.org>
Signed-off-by: Rafael J. Wysocki <email@example.com>
Rafael J. Wysocki