drivers: core: Detach device from power domain on shutdown

drivers: core: Detach device from power domain on shutdown

When the system is powered off or rebooted, devices are not detached
from their PM domain. This results in ACPI PM not being invoked and
hence PowerResouce _OFF method not being invoked for any of the
devices. Because the ACPI power resources are not turned off in case
of poweroff and reboot, it violates the power sequencing requirements
which impacts the reliability of the devices over the lifetime of the
platform. This is currently observed on all Chromebooks using ACPI.

In order to solve the above problem, this change detaches a device
from its PM domain whenever it is shutdown. This action is basically
analogous to ->remove() from driver model perspective. Detaching the
device from its PM domain ensures that the ACPI PM gets a chance to
turn off the power resources for the device thus complying with its
power sequencing requirements.

Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Furquan Shaikh <furquan@google.com>
Link: https://lore.kernel.org/r/20201201213019.1558738-1-furquan@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>