Introduce TYPE_PCI_BRIDGE as base type and use PCI_BRIDGE() casts.
Reviewed-by: NDon Koch <dkoch@verizon.com>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>
[AF: Updated pbm-bridge parent to TYPE_PCI_BRIDGE]
Signed-off-by: NAndreas Färber <afaerber@suse.de>