tty: serial: altera_uart: Check for NULL platform_data in probe.

Follow altera_jtag_uart.  This fixes a crash if there is a mistake in the DTS.

Signed-off-by: Yuriy Kozlov <ykozlov@ptcusa.com>
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/altera_uart.c

@@ -556,15 +556,15 @@ static int __devinit altera_uart_probe(struct platform_device *pdev)
 	res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (res_mem)
 		port->mapbase = res_mem->start;
-	else if (platp->mapbase)
+	else if (platp)
 		port->mapbase = platp->mapbase;
 	else
 		return -EINVAL;
 
 	res_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 	if (res_irq)
 		port->irq = res_irq->start;
-	else if (platp->irq)
+	else if (platp)
 		port->irq = platp->irq;
 
 	/* Check platform data first so we can override device node data */