Versions before gcc-4.6 don't support unnamed fields in initializers
(see http://gcc.gnu.org/bugzilla/show_bug.cgi?id=10676).

Offset and OffsetHigh belong to an unnamed struct which is part of an
unnamed union. Therefore the original code does not work with older
versions of gcc.
Signed-off-by: NStefan Weil <sw@weilnetz.de>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>