remove useless include

Originally committed as revision 18906 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/gxfenc.c

@@ -19,7 +19,6 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
-#include "libavutil/fifo.h"
 #include "avformat.h"
 #include "gxf.h"
 #include "riff.h"

libavformat/mxfenc.c

@@ -35,7 +35,6 @@
 #include <math.h>
 #include <time.h>
 
-#include "libavutil/fifo.h"
 #include "libavutil/random_seed.h"
 #include "libavcodec/bytestream.h"
 #include "audiointerleave.h"