USB: Add autosuspend support to the hub driver

This patch (as742b) adds autosuspend/autoresume support to the USB hub
driver.  The largest aspect of the change is that we no longer need a
special flag for root hubs that want to be resumed.  Now every hub is
autoresumed whenever khubd needs to access it.

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