atheros: define a common priv struct

hw code should never use private driver data, but
sometimes we need a backpointer so just stuff it on
the common ath struct.

Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath.h b/drivers/net/wireless/ath/ath.h
index e0341fe..b6cd752 100644
--- a/drivers/net/wireless/ath/ath.h
+++ b/drivers/net/wireless/ath/ath.h
@@ -56,6 +56,7 @@
 
 struct ath_common {
 	void *ah;
+	void *priv;
 	struct ieee80211_hw *hw;
 	int debug_mask;