ar9170: load firmware asynchronously

This converts ar9170 to load firmware asynchronously
out of ->probe() and only register with mac80211 when
all firmware has been loaded successfully. If, on the
other hand, any firmware fails to load, it will now
unbind from the device.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ar9170/main.c b/drivers/net/wireless/ath/ar9170/main.c
index 8a964f1..f4650fc 100644
--- a/drivers/net/wireless/ath/ar9170/main.c
+++ b/drivers/net/wireless/ath/ar9170/main.c
@@ -2701,7 +2701,8 @@
 	dev_info(pdev, "Atheros AR9170 is registered as '%s'\n",
 		 wiphy_name(ar->hw->wiphy));
 
-	return err;
+	ar->registered = true;
+	return 0;
 
 err_unreg:
 	ieee80211_unregister_hw(ar->hw);
@@ -2712,11 +2713,14 @@
 
 void ar9170_unregister(struct ar9170 *ar)
 {
+	if (ar->registered) {
 #ifdef CONFIG_AR9170_LEDS
-	ar9170_unregister_leds(ar);
+		ar9170_unregister_leds(ar);
 #endif /* CONFIG_AR9170_LEDS */
 
-	kfree_skb(ar->rx_failover);
 	ieee80211_unregister_hw(ar->hw);
+	}
+
+	kfree_skb(ar->rx_failover);
 	mutex_destroy(&ar->mutex);
 }