avutil/eval: Don't include avutil.h

It has been added for an FF_API_* at a time when these were in avutil.h.
Reviewed-by: Martin Storsjö <martin@martin.st>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

libavutil/eval.h

@@ -26,8 +26,6 @@
 #ifndef AVUTIL_EVAL_H
 #define AVUTIL_EVAL_H
 
-#include "avutil.h"
-
 typedef struct AVExpr AVExpr;
 
 /**