USB: UHCI: report non-PME wakeup signalling for Intel hardware

The UHCI controllers in Intel chipsets rely on a platform-specific non-PME
mechanism for wakeup signalling.  They can generate wakeup signals even
though they don't support PME.

We need to let the USB core know this so that it will enable runtime
suspend for UHCI controllers.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CC: stable@vger.kernel.org