USB: EHCI: add a short delay to the bus_suspend routine

This patch (as1031) adds a short delay to the bus-suspend routine in
ehci-hcd.  Without it some devices disconnect when they should
suspend.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: David Brownell <david-b@pacbell.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>