ffmpeg: Don't include colorspace.h

The header is private, and ffmpeg.c doesn't use it
for anything.

Signed-off-by: Derek Buitenhuis <derek.buitenhuis@gmail.com>

ffmpeg.c

@@ -46,7 +46,6 @@
 #include "libavutil/channel_layout.h"
 #include "libavutil/parseutils.h"
 #include "libavutil/samplefmt.h"
-#include "libavutil/colorspace.h"
 #include "libavutil/fifo.h"
 #include "libavutil/intreadwrite.h"
 #include "libavutil/dict.h"