ath: move the rx bufsize to common to share with ath5k/ath9k

This will also be used by ath9k_htc.

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 b3c8ee0..4af1362 100644
--- a/drivers/net/wireless/ath/ath.h
+++ b/drivers/net/wireless/ath/ath.h
@@ -87,6 +87,8 @@
 	u8 tx_chainmask;
 	u8 rx_chainmask;
 
+	u32 rx_bufsize;
+
 	struct ath_regulatory regulatory;
 	const struct ath_ops *ops;
 	const struct ath_bus_ops *bus_ops;