serial: max3107: Fix gpiolib support

Because of the way gpiolib works we actually need to ifdef this in our
header file

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/serial/max3107.h

@@ -368,8 +368,10 @@ struct max3107_port {
 	/* SPI device structure */
 	struct spi_device *spi;
 
+#if defined(CONFIG_GPIOLIB)
 	/* GPIO chip stucture */
 	struct gpio_chip chip;
+#endif
 
 	/* Workqueue that does all the magic */
 	struct workqueue_struct *workqueue;