ACPI / hotplug: Generate online uevents for ACPI containers

ACPI / hotplug: Generate online uevents for ACPI containers

commit 8ab17fc92e49bc2b8fff9d220c19bf50ec9c1158 upstream.

Commit 46394fd01 (ACPI / hotplug: Move container-specific code out of
the core) removed the generation of "online" uevents for containers,
because "add" uevents are now generated for them automatically when
container system devices are registered.  However, there are user
space tools that need to be notified when the container and all of
its children have been enumerated, which doesn't happen any more.

For this reason, add a mechanism allowing "online" uevents to be
generated for ACPI containers after enumerating the container along
with all of its children.

Fixes: 46394fd01 (ACPI / hotplug: Move container-specific code out of the core)
Reported-and-tested-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>