AVI: add bswap.h include needed on big endian

Originally committed as revision 16564 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/avidec.c

@@ -18,6 +18,8 @@
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
+
+#include "libavutil/bswap.h"
 #include "avformat.h"
 #include "avi.h"
 #include "dv.h"