ath9k: Add "debug" file to debugfs

This patch adds the debug file to the ath9k debugfs, which lets you modify
the debug_mask at runtime, without having to reload the ath9k module.

Signed-off-by: Jeff Hansen <x@jeffhansen.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath9k/debug.h b/drivers/net/wireless/ath/ath9k/debug.h
index cf9146a..edda15b 100644
--- a/drivers/net/wireless/ath/ath9k/debug.h
+++ b/drivers/net/wireless/ath/ath9k/debug.h
@@ -95,6 +95,7 @@
 struct ath9k_debug {
 	int debug_mask;
 	struct dentry *debugfs_phy;
+	struct dentry *debugfs_debug;
 	struct dentry *debugfs_dma;
 	struct dentry *debugfs_interrupt;
 	struct dentry *debugfs_rcstat;