ath9k: Add ATH9K_DEBUG configuration option

Make debugging configurable, and add a module parameter
to give the debug mask.
Add debug.c to hold all debug specific code.

Signed-off-by: Sujith <Sujith.Manoharan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath9k/Kconfig b/drivers/net/wireless/ath9k/Kconfig
index 80a6924..c43bd32 100644
--- a/drivers/net/wireless/ath9k/Kconfig
+++ b/drivers/net/wireless/ath9k/Kconfig
@@ -9,3 +9,14 @@
 	  Atheros IEEE 802.11n AR5008 and AR9001 family of chipsets.
 
 	  If you choose to build a module, it'll be called ath9k.
+
+config ATH9K_DEBUG
+	bool "Atheros ath9k debugging"
+	depends on ATH9K
+	---help---
+	  Say Y, if you need ath9k to display debug messages.
+	  Pass the debug mask as a module parameter:
+
+	  modprobe ath9k debug=0x00002000
+
+	  Look in ath9k/core.h for possible debug masks