ath5k: Fix bitmasks and typos for PCU Diagnostic register

As reported by Ryan Niemi, some bitmasks in the register definition for the PCU
Diagnostic register (DIAG_SW) were missing a zero at the end. While at it fix
some typos and add more comments.

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/dma.c b/drivers/net/wireless/ath/ath5k/dma.c
index 58bb6c5..923c9ca 100644
--- a/drivers/net/wireless/ath/ath5k/dma.c
+++ b/drivers/net/wireless/ath/ath5k/dma.c
@@ -244,7 +244,7 @@
 
 			/* Force channel idle high */
 			AR5K_REG_ENABLE_BITS(ah, AR5K_DIAG_SW_5211,
-					AR5K_DIAG_SW_CHANEL_IDLE_HIGH);
+					AR5K_DIAG_SW_CHANNEL_IDLE_HIGH);
 
 			/* Wait a while and disable mechanism */
 			udelay(200);
@@ -261,7 +261,7 @@
 			} while (--i && pending);
 
 			AR5K_REG_DISABLE_BITS(ah, AR5K_DIAG_SW_5211,
-					AR5K_DIAG_SW_CHANEL_IDLE_HIGH);
+					AR5K_DIAG_SW_CHANNEL_IDLE_HIGH);
 		}
 
 		/* Clear register */