greybus: gpio: kill gpio_controller->gpio

This field is never used (and not needed) so get rid of it.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

drivers/staging/greybus/gpio-gb.c

@@ -29,7 +29,6 @@ struct gb_gpio_controller {
 	struct gb_gpio_line	*lines;
 
 	struct gpio_chip	chip;
-	struct gpio_chip	*gpio;
 };
 #define gpio_chip_to_gb_gpio_controller(chip) \
 	container_of(chip, struct gb_gpio_controller, chip)