ath9k_hw: fix a comment

also remove an unused macro and a function declaration

Signed-off-by: Mohammed Shafi Shajakhan <mohammed@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath9k/ar9003_phy.c b/drivers/net/wireless/ath/ath9k/ar9003_phy.c
index 2589b38..2b0bfb8 100644
--- a/drivers/net/wireless/ath/ath9k/ar9003_phy.c
+++ b/drivers/net/wireless/ath/ath9k/ar9003_phy.c
@@ -46,7 +46,7 @@
  * @chan:
  *
  * This is the function to change channel on single-chip devices, that is
- * all devices after ar9280.
+ * for AR9300 family of chipsets.
  *
  * This function takes the channel value in MHz and sets
  * hardware channel value. Assumes writes have been enabled to analog bus.