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>

libavformat/utils.c

@@ -25,7 +25,6 @@
 #include "libavcodec/internal.h"
 #include "libavcodec/raw.h"
 #include "libavcodec/bytestream.h"
-#include "libavutil/accessors.h"
 #include "libavutil/avassert.h"
 #include "libavutil/opt.h"
 #include "libavutil/dict.h"