avcodec/interplayvideo: Avoid ff_get_buffer() during init

This is unneeded for interplay video

Fixes: memleak
Fixes: 15562/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_INTERPLAY_VIDEO_fuzzer-5162268645392384

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/interplayvideo.c

@@ -1181,14 +1181,6 @@ static av_cold int ipvideo_decode_init(AVCodecContext *avctx)
     s->cur_decode_frame->format  = avctx->pix_fmt;
     s->prev_decode_frame->format = avctx->pix_fmt;
 
-    ret = ff_get_buffer(avctx, s->cur_decode_frame, 0);
-    if (ret < 0)
-        goto error;
-
-    ret = ff_get_buffer(avctx, s->prev_decode_frame, 0);
-    if (ret < 0)
-        goto error;
-
     return 0;
 error:
     av_frame_free(&s->last_frame);