I'm not sure why ah_desc.h was required here, but it doesn't _need_

to be. So, just toss it.

There's no options or ah_desc fields in here.

Whilst I'm here, fix up the #ifdef and #define to mach.

sys/dev/ath/ath_hal/ar5416/ar5416desc.h

@@ -17,12 +17,11 @@
  * $FreeBSD$
  */
 #ifndef _ATH_AR5416_DESC_H_
-#define _ATH_AR5416_DESC_H
+#define _ATH_AR5416_DESC_H_
 
 /*
  * Hardware-specific descriptor structures.
  */
-#include "ah_desc.h"
 
 /* XXX Need to replace this with a dynamic 
  * method of determining Owl2 if possible