firewire: ohci: pass correct iso xmit timestamps to core

Here is the final set of patches I used to get ffado to work with the
new firewire stack.  With these patches, I was able to start ardour
and record from and playback to my PreSonus Inspire1394 from a
(mostly) Fedora 12 system.

Signed-off-by: Jay Fenlason <fenlason@redhat.com>

Until now, firewire-ohci exposed only the transmit cycle of the last
transmitted packet at each isochronous transmit complete event.  This
made it impossible for FFADO (FireWire audio drivers in userspace) to
synchronize audio-out streams.  The fix is to store the timestamp of
each packet in the iso xmit event.  As a bonus, the transfer status is
stored too.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>