EHCI: turn off remote wakeup during shutdown

This patch (as850b) disables remote wakeup (and everything else!) on
all EHCI ports when the shutdown() method is called.  If remote wakeup
is left active then some systems will reboot instead of powering off.
This fixes Bugzilla #7828.

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