ath5k: Use generic EWMA library

Remove ath5k's private moving average implementation in favour of the generic
library version.

Signed-off-by: Bruno Randolf <br1@einfach.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath5k/debug.c b/drivers/net/wireless/ath/ath5k/debug.c
index 54dcf77..7d785cb6 100644
--- a/drivers/net/wireless/ath/ath5k/debug.c
+++ b/drivers/net/wireless/ath/ath5k/debug.c
@@ -719,7 +719,7 @@
 			st->mib_intr);
 	len += snprintf(buf+len, sizeof(buf)-len,
 			"beacon RSSI average:\t%d\n",
-			sc->ah->ah_beacon_rssi_avg.avg);
+			(int)ewma_read(&sc->ah->ah_beacon_rssi_avg));
 
 #define CC_PRINT(_struct, _field) \
 	_struct._field, \