ath5k: clarify srev comparison for CCMP check

As Pavel Roskin noted, the check for mac version as copied from
legacy_hal made no sense.  This replaces it with the equivalent
and makes up a suitable #define for the mac version legacy_hal
checked.

Signed-off-by: Bob Copeland <me@bobcopeland.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath5k/ath5k.h b/drivers/net/wireless/ath/ath5k/ath5k.h
index cdc79cd..1275ba0 100644
--- a/drivers/net/wireless/ath/ath5k/ath5k.h
+++ b/drivers/net/wireless/ath/ath5k/ath5k.h
@@ -306,6 +306,7 @@
 #define AR5K_SREV_AR5311B	0x30 /* Spirit */
 #define AR5K_SREV_AR5211	0x40 /* Oahu */
 #define AR5K_SREV_AR5212	0x50 /* Venice */
+#define AR5K_SREV_AR5212_V4	0x54 /* ??? */
 #define AR5K_SREV_AR5213	0x55 /* ??? */
 #define AR5K_SREV_AR5213A	0x59 /* Hainan */
 #define AR5K_SREV_AR2413	0x78 /* Griffin lite */