uhci-hcd.c currently calls usb_endpoint_halt() in the td_error: path of
uhci_result_control().  David Brownell told me that "control endpoints
don't halt" and that this is wrong.  The patch below fixes this and allows
my Belkin Universal UPS to work.  [Although it still prints lots of
"drivers/usb/input/hid-core.c: ctrl urb status -32 received" messages.]
Greg K-H, could you merge this if it looks right?  David mentioned that
the same bug exists in 2.4.x.