Fix make checkheaders by adding missing #include.

Originally committed as revision 10948 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/huffman.h

@@ -24,6 +24,7 @@
 #define FFMPEG_HUFFMAN_H
 
 #include "avcodec.h"
+#include "bitstream.h"
 
 typedef struct {
     int16_t  sym;