avcodec/tiff: add a zero DNG_LINEARIZATION_TABLE check

Fixes: index 4294967295 out of bounds for type 'uint16_t [65536]'
Fixes: 45982/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_TIFF_fuzzer-5950405086674944
Fixes: 45982/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_TIFF_fuzzer-6666195176914944

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

libavcodec/tiff.c

@@ -1451,7 +1451,7 @@ static int tiff_decode_tag(TiffContext *s, AVFrame *frame)
         break;
     case TIFF_GRAY_RESPONSE_CURVE:
     case DNG_LINEARIZATION_TABLE:
-        if (count > FF_ARRAY_ELEMS(s->dng_lut))
+        if (count < 1 || count > FF_ARRAY_ELEMS(s->dng_lut))
             return AVERROR_INVALIDDATA;
         for (int i = 0; i < count; i++)
             s->dng_lut[i] = ff_tget(&s->gb, type, s->le);