Integrate accessors.h header into internal.h

I have no idea why I added a separate header,
I think there is no good reason for it.

Signed-off-by: Reimar Döffinger <Reimar.Doeffinger@gmx.de>

libavcodec/utils.c

@@ -26,7 +26,6 @@
  */
 
 #include "config.h"
-#include "libavutil/accessors.h"
 #include "libavutil/atomic.h"
 #include "libavutil/attributes.h"
 #include "libavutil/avassert.h"