ath9k: remove warnings related to signed/unsigned type mismatch

CC [M]  drivers/net/wireless/ath/ath9k/recv.o
drivers/net/wireless/ath/ath9k/recv.c: In function `ath_rx_prepare':
drivers/net/wireless/ath/ath9k/recv.c:208: warning: comparison is always true due to limited range of data type
drivers/net/wireless/ath/ath9k/recv.c:220: warning: comparison is always false due to limited range of data type
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath9k/common.c

@@ -181,8 +181,6 @@ static void ath9k_process_rssi(struct ath_common *common,
 					      ATH_RSSI_EP_MULTIPLIER);
 	if (rx_stats->rs_rssi < 0)
 		rx_stats->rs_rssi = 0;
-	else if (rx_stats->rs_rssi > 127)
-		rx_stats->rs_rssi = 127;
 
 	/* Update Beacon RSSI, this is used by ANI. */
 	if (ieee80211_is_beacon(fc))

drivers/net/wireless/ath/ath9k/hw.h

@@ -60,7 +60,7 @@
 
 #define	ATH_DEFAULT_NOISE_FLOOR -95
 
-#define ATH9K_RSSI_BAD			0x80
+#define ATH9K_RSSI_BAD			-128
 
 /* Register read/write primitives */
 #define REG_WRITE(_ah, _reg, _val) \