spapr: generate DT node names

spapr: generate DT node names

When DT node names for PCI devices are generated by SLOF,
they are generated according to the type of the device
(for instance, ethernet for virtio-net-pci device).

Node name for hotplugged devices is generated by QEMU.
This patch adds the mechanic to QEMU to create the node
name according to the device type too.

The data structure has been roughly copied from OpenBIOS/OpenHackware,
node names from SLOF.

Example:

Hotplugging some PCI cards with QEMU monitor:

device_add virtio-tablet-pci
device_add virtio-serial-pci
device_add virtio-mouse-pci
device_add virtio-scsi-pci
device_add virtio-gpu-pci
device_add ne2k_pci
device_add nec-usb-xhci
device_add intel-hda

What we can see in linux device tree:

for dir in /proc/device-tree/pci@800000020000000/*@*/; do
    echo $dir
    cat $dir/name
    echo
done

WITHOUT this patch:

/proc/device-tree/pci@800000020000000/pci@0/
pci
/proc/device-tree/pci@800000020000000/pci@1/
pci
/proc/device-tree/pci@800000020000000/pci@2/
pci
/proc/device-tree/pci@800000020000000/pci@3/
pci
/proc/device-tree/pci@800000020000000/pci@4/
pci
/proc/device-tree/pci@800000020000000/pci@5/
pci
/proc/device-tree/pci@800000020000000/pci@6/
pci
/proc/device-tree/pci@800000020000000/pci@7/
pci

WITH this patch:

/proc/device-tree/pci@800000020000000/communication-controller@1/
communication-controller
/proc/device-tree/pci@800000020000000/display@4/
display
/proc/device-tree/pci@800000020000000/ethernet@5/
ethernet
/proc/device-tree/pci@800000020000000/input-controller@0/
input-controller
/proc/device-tree/pci@800000020000000/mouse@2/
mouse
/proc/device-tree/pci@800000020000000/multimedia-device@7/
multimedia-device
/proc/device-tree/pci@800000020000000/scsi@3/
scsi
/proc/device-tree/pci@800000020000000/usb-xhci@6/
usb-xhci

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