This patch fixes a tiny SMP-type hole in root-hub synchronization.
Although the HCD glue layer properly unlinks root-hub status URBs
synchronously, it doesn't do so for URBs sent to endpoint 0.  This patch
copies some code from usb_kill_urb, to make such unlinks wait until the
host controller driver has finished handling the URB.  This behavior is
required for hcd_endpoint_disable to work correctly.

The patch also renames usb_rh_status_dequeue to usb_rh_urb_dequeue (to
better describe its updated function) and declares the routine static.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>