atheros: add common debug printing

ath9k uses this for now, ath9k_htc is expected to re-use this
as well. We lave ath5k as is, but it certainly can also be
converted later.

The ath9k module parameter and debugfs entry is kept.

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 8865413..2ca9701 100644
--- a/drivers/net/wireless/ath/ath.h
+++ b/drivers/net/wireless/ath/ath.h
@@ -48,11 +48,14 @@
 struct ath_common {
 	void *ah;
 	struct ieee80211_hw *hw;
+	int debug_mask;
+
 	u16 cachelsz;
 	u16 curaid;
 	u8 macaddr[ETH_ALEN];
 	u8 curbssid[ETH_ALEN];
 	u8 bssidmask[ETH_ALEN];
+
 	struct ath_regulatory regulatory;
 	const struct ath_ops *ops;
 };