ath5k: Use high bitrates for ACK/CTS

There was a confusion in the usage of the bits AR5K_STA_ID1_ACKCTS_6MB and
AR5K_STA_ID1_BASE_RATE_11B. If they are set (1), we will get lower bitrates for
ACK and CTS. Therefore ath5k_hw_set_ack_bitrate_high(ah, false) actually
resulted in high bitrates, which i think is what we want anyways. Cleared the
confusion and added some documentation.

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/base.c b/drivers/net/wireless/ath/ath5k/base.c
index f7f57c1..3f59bc2 100644
--- a/drivers/net/wireless/ath/ath5k/base.c
+++ b/drivers/net/wireless/ath/ath5k/base.c
@@ -2558,8 +2558,7 @@
 	for (i = 0; i < AR5K_KEYTABLE_SIZE; i++)
 		ath5k_hw_reset_key(ah, i);
 
-	/* Set ack to be sent at low bit-rates */
-	ath5k_hw_set_ack_bitrate_high(ah, false);
+	ath5k_hw_set_ack_bitrate_high(ah, true);
 	ret = 0;
 done:
 	mmiowb();