Revert "usb: musb: fix tx fifo flush handling again"

This reverts commit 98b91bfa which is
commit 45d73860 upstream.

It should not have been applied to the 3.18-stable tree at all.

Reported-by: Greg Kaiser <gkaiser@google.com>
Cc: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>