serial: omap: Initialize platform_data

Otherwise serial driver would crash accessing platform_data that was
not initialized in functions like:

        serial_omap_pm(...)
        ...
        if (!state && pdata->enable_wakeup)
                   ^^^^^^^
        ...

Signed-off-by: Vikram Pandita <vikram.pandita@ti.com>
Signed-off-by: Alexander Savchenko <oleksandr.savchenko@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/omap-serial.c

@@ -1414,8 +1414,10 @@ static int serial_omap_probe(struct platform_device *pdev)
 	struct omap_uart_port_info *omap_up_info = pdev->dev.platform_data;
 	int ret;
 
-	if (pdev->dev.of_node)
+	if (pdev->dev.of_node) {
 		omap_up_info = of_get_uart_port_info(&pdev->dev);
+		pdev->dev.platform_data = omap_up_info;
+	}
 
 	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (!mem) {