avcodec/cfhdenc: Height of 16 is not supported

Fixes: out of array access
Fixes: 68941/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_CFHD_fuzzer-5990952685600768

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

libavcodec/cfhdenc.c

@@ -257,8 +257,8 @@ static av_cold int cfhd_encode_init(AVCodecContext *avctx)
     if (ret < 0)
         return ret;
 
-    if (avctx->height < 4) {
+    if (avctx->height < 32) {
-        av_log(avctx, AV_LOG_ERROR, "Height must be >= 4.\n");
+        av_log(avctx, AV_LOG_ERROR, "Height must be >= 32.\n");
         return AVERROR_INVALIDDATA;
     }