b43: Fix possible MMIO access while device is down

Index: linux-2.6.25.9/drivers/net/wireless/b43/leds.c
===================================================================
@@ -69,12 +69,15 @@ static void b43_led_brightness_set(struc
 				   enum led_brightness brightness)
 {
 	struct b43_led *led = container_of(led_dev, struct b43_led, led_dev);
 	struct b43_wldev *dev = led->dev;
 	bool radio_enabled;
 
+	if (unlikely(b43_status(dev) < B43_STAT_INITIALIZED))
+		return;
+
 	/* Checking the radio-enabled status here is slightly racy,
 	 * but we want to avoid the locking overhead and we don't care
 	 * whether the LED has the wrong state for a second. */
 	radio_enabled = (dev->phy.radio_on && dev->radio_hw_enable);
 
 	if (brightness == LED_OFF || !radio_enabled)