In some situations we can receive the ORB status write before we
have received the ORB pointer write response.  When this happens,
we assume that the fw_transaction is finished and free the ORB
struct containing the fw_transaction.

This fix make the status write logic only accept status writes
for ORBs where the initial ORB pointer write transaction finished.
Signed-off-by: Kristian Høgsberg <krh@redhat.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>