ath9k: Make DMA warning in ath_stoprecv WARN_ON_ONCE.

This decreases spammage in the log.  A single line message
will still be printed, so users can be aware that problem
exists.

Signed-off-by: Ben Greear <greearb@candelatech.com>
Acked-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 dd78ad1..272dfef 100644
--- a/drivers/net/wireless/ath/ath.h
+++ b/drivers/net/wireless/ath/ath.h
@@ -267,6 +267,7 @@
 	rtn;							\
 })
 #define ATH_DBG_WARN(foo, arg...) WARN(foo, arg)
+#define ATH_DBG_WARN_ON_ONCE(foo) WARN_ON_ONCE(foo)
 
 #else
 
@@ -277,6 +278,7 @@
 	return 0;
 }
 #define ATH_DBG_WARN(foo, arg...) do {} while (0)
+#define ATH_DBG_WARN_ON_ONCE(foo) do {} while (0)
 
 #endif /* CONFIG_ATH_DEBUG */