serial: pch_uart: Make port type explicit

It used to be a gap in port definitions after PORT_MAX_8250. Since the
new drivers are coming the gap become shorter and shorter until the
commit a2d6a987 ("serial: 8250: Add new port type for TI DA8xx/66AK2x")
completely removed it.

So, while type here is just a formality, make things a little bit more
explicit for this driver and move port types to UAPI header. Note,
it uses two types for now.

Fixes: fddceb8b ("tty: 8250: Add 64byte UART support for FSL platforms")
Cc: Priyanka Jain <Priyanka.Jain@freescale.com>
Cc: Poonam Aggrwal <poonam.aggrwal@freescale.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>