PCI: add missing classes in pci_ids.h to build device tree

To allow QEMU to add PCI entries in device tree,
we must have a more exhaustive list of PCI class IDs.

This patch synchronizes as much as possible with
pci_ids.h and add some missing IDs from SLOF.

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
