fate-utvideoenc: remove unneeded -f avi

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

tests/fate/utvideo.mak

@@ -28,7 +28,7 @@ fate-utvideo_yuv422_median: CMD = framecrc -i $(SAMPLES)/utvideo/utvideo_yuv422_
 FATE_SAMPLES_AVCONV += $(FATE_UTVIDEO)
 fate-utvideo: $(FATE_UTVIDEO)
 
-fate-utvideoenc%: CMD = framemd5 -f image2 -vcodec pgmyuv -i $(TARGET_PATH)/tests/vsynth1/%02d.pgm -vcodec utvideo -f avi -sws_flags +accurate_rnd+bitexact ${OPTS}
+fate-utvideoenc%: CMD = framemd5 -f image2 -vcodec pgmyuv -i $(TARGET_PATH)/tests/vsynth1/%02d.pgm -vcodec utvideo -sws_flags +accurate_rnd+bitexact ${OPTS}
 
 FATE_UTVIDEOENC += fate-utvideoenc_rgba_none
 fate-utvideoenc_rgba_none: OPTS = -pix_fmt rgba -pred 3