Fix redefinition of typedef 'Accounting'

Fix for the following warning:
redefinition of typedef 'Accounting' is a C11 feature

Change-Id: I1ac074e2f0bb1694d4069a20defaed4706c89c5c

aom/aomdx.h

@@ -37,11 +37,9 @@ extern aom_codec_iface_t aom_codec_av1_dx_algo;
 extern aom_codec_iface_t *aom_codec_av1_dx(void);
 /*!@} - end algorithm interface member group*/
 
-#ifndef AOM_ACCOUNTING_H_
 /** Data structure that stores bit accounting for debug
  */
 typedef struct Accounting Accounting;
-#endif
 
 #ifndef AOM_INSPECTION_H_
 /** Callback that inspects decoder frame data.

av1/decoder/accounting.h

@@ -11,6 +11,7 @@
 #ifndef AOM_ACCOUNTING_H_
 #define AOM_ACCOUNTING_H_
 #include <stdlib.h>
+#include "aom/aomdx.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -58,8 +59,6 @@ typedef struct {
   AccountingDictionary dictionary;
 } AccountingSymbols;
 
-typedef struct Accounting Accounting;
-
 struct Accounting {
   AccountingSymbols syms;
   /** Size allocated for symbols (not all may be used). */