bcma: unregister gpios before unloading bcma

This patch unregisters the gpio chip before bcma gets unloaded.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Reported-by: Piotr Haber <phaber@broadcom.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/bcma/driver_gpio.c

@@ -96,3 +96,8 @@ int bcma_gpio_init(struct bcma_drv_cc *cc)
 
 	return gpiochip_add(chip);
 }
+
+int bcma_gpio_unregister(struct bcma_drv_cc *cc)
+{
+	return gpiochip_remove(&cc->gpio);
+}