Convert pci_delete_child() to a bus_child_deleted() method.

Convert pci_delete_child() to a bus_child_deleted() method.

Instead of providing a wrapper around device_delete_child() that the PCI
bus and child bus drivers must call explicitly, move the bulk of the logic
from pci_delete_child() into a bus_child_deleted() method
(pci_child_deleted()).  This allows PCI devices to be safely deleted via
device_delete_child().
- Add a bus_child_deleted method to the ACPI PCI bus which clears the
  device_t associated with the corresponding ACPI handle in addition to
  the normal PCI bus cleanup.
- Change cardbus_detach_card to call device_delete_children() and move
  CardBus-specific delete logic into a new cardbus_child_deleted() method.
- Use device_delete_child() instead of pci_delete_child() in the SRIOV code.
- Add a bus_child_deleted method to the OpenFirmware PCI bus drivers which
  frees the OpenFirmware device info for each PCI device.

To preserve KBI, a pci_delete_child() function is left in place that
just calls device_delete_child().

PR:		226562
Requested by:	dexuan

git-svn-id: svn://svn.freebsd.org/base/stable/10@330938 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f