ssb/gpio: Remove unnecessary WARN_ON from driver_gpio

The WARN_ON triggers on older BCM4401-B0 100Base-TX ethernet controllers.
The warning serves no purpose. So let's just remove it.

Reported-by: H Buus <ubuntu@hbuus.com>
Signed-off-by: Michael Büsch <m@bues.ch>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/ssb/driver_gpio.c

@@ -460,9 +460,6 @@ int ssb_gpio_init(struct ssb_bus *bus)
 		return ssb_gpio_chipco_init(bus);
 	else if (ssb_extif_available(&bus->extif))
 		return ssb_gpio_extif_init(bus);
-	else
-		WARN_ON(1);
-
 	return -1;
 }
 
@@ -472,9 +469,6 @@ int ssb_gpio_unregister(struct ssb_bus *bus)
 	    ssb_extif_available(&bus->extif)) {
 		gpiochip_remove(&bus->gpio);
 		return 0;
-	} else {
-		WARN_ON(1);
 	}
-
 	return -1;
 }