serial: cast before shifting on port io

Without this we will shift data into oblivion and give wrong results on
some configurations
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/serial_core.c

@@ -2366,7 +2366,7 @@ static ssize_t uart_get_attr_port(struct device *dev,
 	struct tty_port *port = dev_get_drvdata(dev);
 
 	uart_get_info(port, &tmp);
-	return snprintf(buf, PAGE_SIZE, "0x%lX\n", (unsigned long)(tmp.port | (tmp.port_high << HIGH_BITS_OFFSET)));
+	return snprintf(buf, PAGE_SIZE, "0x%lX\n", (unsigned long)(tmp.port | (((unsigned long)tmp.port_high) << HIGH_BITS_OFFSET)));
 }
 
 static ssize_t uart_get_attr_irq(struct device *dev,