Re-enable posted writes for status FIFO.
Besides bringing back a very minor bandwidth tweak from Linux 2.6.15.x
and older, this also fixes an interoperability regression since 2.6.16:
http://bugzilla.kernel.org/show_bug.cgi?id=6356


(sbp2: scsi_add_device failed. IEEE1394 HD is not working anymore.)

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Tested-by: Vanei Heidemann <linux@javanei.com.br>
Tested-by: Martin Putzlocher <mputzi@gmx.de> (chip type unconfirmed)
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>