ACPI / dock / PCI: Synchronous handling of dock events for PCI devices

The interactions between the ACPI dock driver and the ACPI-based PCI
hotplug (acpiphp) are currently problematic because of ordering
issues during hot-remove operations.

First of all, the current ACPI glue code expects that physical
devices will always be deleted before deleting the companion ACPI
device objects.  Otherwise, acpi_unbind_one() will fail with a
warning message printed to the kernel log, for example:

[  185.026073] usb usb5: Oops, 'acpi_handle' corrupt
[  185.035150] pci 0000:1b:00.0: Oops, 'acpi_handle' corrupt
[  185.035515] pci 0000:18:02.0: Oops, 'acpi_handle' corrupt
[  180.013656]  port1: Oops, 'acpi_handle' corrupt

This means, in particular, that struct pci_dev objects have to
be deleted before the struct acpi_device objects they are "glued"
with.

Now, the following happens the during the undocking of an ACPI-based
dock station:
 1) hotplug_dock_devices() invokes registered hotplug callbacks to
    destroy phys...