serial: 8250_pci: add .probe member to struct pci_serial_quirk

This function, if present, is called early on by the 8250_pci probe; it
can be used to reject devices meant for parport_serial.  (The .init
function cannot be used for this purpose, as it is also called by
parport_serial.)

Signed-off-by: Frédéric Brière <fbriere@fbriere.net>
Acked-by: Alan Cox <alan@linux.intel.com>
Cc: linux-serial@vger.kernel.org
Cc: linux-parport@lists.infradead.org
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>