USB: revert periodic scheduling bugfix

USB: revert periodic scheduling bugfix

This patch reverts commit 254f7295a507874062b97fe9d89ca6e28c1d03d9
(USB: EHCI: fix bug in scheduling periodic split transfers).  The
commit was valid -- it fixed a real bug -- but the periodic scheduler
in ehci-hcd is in such bad shape (especially the part that handles
split transactions) that fixing one bug is very likely to cause
another to surface.  That's what happened in this case; the result was
choppy and noisy playback on certain 24-bit audio devices.

The only real fix will be to rewrite this entire section of code.  My
next project...

This fixes https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1136110.

Thanks to Tim Richardson for extra testing and feedback, and to Joseph
Salisbury and Tyson Tan for tracking down the original source of the
problem.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: Joseph Salisbury <joseph.salisbury@canonical.com>
CC: Tim Richardson <tim@tim-richardson.net>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>