avfilter/internal: Don't include video.h

internal.h does not depend on video.h (and should not depend on it)
and therefore should not include video.h at all; instead all users
of video.h should include it directly.

Doing so also avoids unnecessary video.h inclusions in files that
don't need it, like most audio filters.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

libavfilter/af_anequalizer.c

@@ -27,6 +27,7 @@
 #include "avfilter.h"
 #include "internal.h"
 #include "audio.h"
+#include "video.h"
 
 #define FILTER_ORDER 4