usb-uhci: correctly deal with interrupt in asynchronous completion

usb-uhci: correctly deal with interrupt in asynchronous completion

This is the result of merging the remaining changes from:

    changeset:   12775:60bbcf799384d779c2a561b9d9ba30f28e31d970
    user:        kfraser@localhost.localdomain
    date:        Thu Dec 07 11:52:26 2006 +0000
    files:       tools/ioemu/hw/usb-hid.c tools/ioemu/hw/usb-uhci.c
    description:
    [HVM] qemu mouse: Adds support for USB mouse/tablet status check and
    restricts Universal Host Controller interrupt generating when received
    NAK in interrupt transfer.

    According to usb spec, USB mouse/tablet device returns NAK to host
    controller if its status does not alter in interrupt transfer.
    And UHC should leave a TD active when receiving NAK and execute this
    incompleted TD in a subseqent frame. UHC only generates an interrupt
    on complete after the TD with ICO bit is completed.

    This patch make UHC & USB mouse/tablet behave consistently with spec.

    Signed-off-by: Xinmei Huang <xinmei.huang@intel.com>
The tablet NAK support was already done in qemu, but there was still
what Xinmei Huang tell us is a spurious interrupt in the case of
submission for asynchronous completion.

Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>