drivers/serial/atmel_serial.c: fix compile when CONFIG_SERIAL_ATMEL=Y and CONFIG_SERIAL_ATMEL_CONSOLE=N

When SERIAL_ATMEL_CONSOLE is disabled, ATMEL_CONSOLE_DEVICE is set to
NULL, and trying to access ATMEL_CONSOLE_DEVICE->flags in
atmel_serial_probe makes the compile fail.  This fixes the issue by only
accessing it if CONFIG_SERIAL_ATMEL_CONSOLE is defined

Signed-off-by: Albin Tonnerre <albin.tonnerre@free-electrons.com>
Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
Cc: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/serial/atmel_serial.c

@@ -1551,6 +1551,7 @@ static int __devinit atmel_serial_probe(struct platform_device *pdev)
 	if (ret)
 		goto err_add_port;
 
+#ifdef CONFIG_SERIAL_ATMEL_CONSOLE
 	if (atmel_is_console_port(&port->uart)
 			&& ATMEL_CONSOLE_DEVICE->flags & CON_ENABLED) {
 		/*
@@ -1559,6 +1560,7 @@ static int __devinit atmel_serial_probe(struct platform_device *pdev)
 		 */
 		clk_disable(port->clk);
 	}
+#endif
 
 	device_init_wakeup(&pdev->dev, 1);
 	platform_set_drvdata(pdev, port);