USB: EHCI: fix handover for designated full-speed ports

This patch (as895) fixes up a loose end in the port-handover code for
the USB-Persist facility.  A special case occurs when a high-speed
device is attached to a port which the user has designated to run at
full-speed only; the port must be disabled before the handover can
take place.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>