cfg80211: add wrapper function to get wiphy from priv pointer

Signed-off-by: David Kilroy <kilroyd@googlemail.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

include/net/cfg80211.h

@@ -1058,6 +1058,17 @@ static inline void *wiphy_priv(struct wiphy *wiphy)
 	return &wiphy->priv;
 }
 
+/**
+ * priv_to_wiphy - return the wiphy containing the priv
+ *
+ * @priv: a pointer previously returned by wiphy_priv
+ */
+static inline struct wiphy *priv_to_wiphy(void *priv)
+{
+	BUG_ON(!priv);
+	return container_of(priv, struct wiphy, priv);
+}
+
 /**
  * set_wiphy_dev - set device pointer for wiphy
  *