ssb: unregister gpios before unloading ssb

This patch unregisters the gpio chip before ssb gets unloaded.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/ssb/driver_gpio.c b/drivers/ssb/driver_gpio.c
index 97ac0a3..eb27530 100644
--- a/drivers/ssb/driver_gpio.c
+++ b/drivers/ssb/driver_gpio.c
@@ -174,3 +174,15 @@
 
 	return -1;
 }
+
+int ssb_gpio_unregister(struct ssb_bus *bus)
+{
+	if (ssb_chipco_available(&bus->chipco) ||
+	    ssb_extif_available(&bus->extif)) {
+		return gpiochip_remove(&bus->gpio);
+	} else {
+		SSB_WARN_ON(1);
+	}
+
+	return -1;
+}