serial: of_serial: Handle fifo-size property

This will reduce the need for extra types in 8250.c just
in case the fifo size differs from the standard.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/devicetree/bindings/tty/serial/of-serial.txt

@@ -33,6 +33,7 @@ Optional properties:
   RTAS and should not be registered.
 - no-loopback-test: set to indicate that the port does not implements loopback
   test mode
+- fifo-size: the fifo size of the UART.
 
 Example:
 

drivers/tty/serial/of_serial.c

@@ -97,6 +97,10 @@ static int of_platform_serial_setup(struct platform_device *ofdev,
 	if (of_property_read_u32(np, "reg-shift", &prop) == 0)
 		port->regshift = prop;
 
+	/* Check for fifo size */
+	if (of_property_read_u32(np, "fifo-size", &prop) == 0)
+		port->fifosize = prop;
+
 	port->irq = irq_of_parse_and_map(np, 0);
 	port->iotype = UPIO_MEM;
 	if (of_property_read_u32(np, "reg-io-width", &prop) == 0) {