Define and use standard QOM cast macro. Remove usages of DO_UPCAST() and
direct -> style casting.
Signed-off-by: NPeter Crosthwaite <peter.crosthwaite@xilinx.com>
[AF: Renamed to TYPE_VMWARE_VGA and VMWARE_VGA()]
Signed-off-by: NAndreas Färber <afaerber@suse.de>