USB: make ksuspend_usbd thread non-freezable

This patch (as1012b) makes the ksuspend_usbd kernel thread
non-freezable.  Since the PM core has been changed to lock all devices
during a system sleep, the thread no longer needs to be frozen.  It
won't interfere with a system sleep because before trying to resume a
root hub device, it acquires the device's lock.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/core/usb.c

@@ -230,7 +230,7 @@ static int ksuspend_usb_init(void)
 	 * singlethreaded.  Its job doesn't justify running on more
 	 * than one CPU.
 	 */
-	ksuspend_usb_wq = create_freezeable_workqueue("ksuspend_usbd");
+	ksuspend_usb_wq = create_singlethread_workqueue("ksuspend_usbd");
 	if (!ksuspend_usb_wq)
 		return -ENOMEM;
 	return 0;