OHCI: disallow autostop when wakeup is not available

This patch (as822) prevents the OHCI autostop mechanism from kicking in
if the root hub is not able or not allowed to issue wakeup requests.

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