USB: fix leftover references to udev->autosuspend_delay

This patch (as1436) takes care of leftover references to
udev->autosuspend_delay that didn't get removed during the earlier
conversion to the runtime-PM autosuspend API.

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