Curerntly the pseries VIO device code contains quite a few explicit
uses of DO_UPCAST and plain C casts.  This is (obviously) type unsafe,
and not the conventional way of doing things in the QOM model.  This
patch converts the code to use the QOM convention of per-type macros
to do verified casts with OBJECT_CHECK().
Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NAlexander Graf <agraf@suse.de>