avcodec/tiff: Check camera_calibration for 0

Fixes: division by 0
Fixes: 53926/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_TIFF_fuzzer-5680347889401856

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

@@ -2050,8 +2050,10 @@ again:
         }
 
         if (!s->use_color_matrix) {
-            for (i = 0; i < 3; i++)
-                s->premultiply[i] /= s->camera_calibration[i][i];
+            for (i = 0; i < 3; i++) {
+                if (s->camera_calibration[i][i])
+                    s->premultiply[i] /= s->camera_calibration[i][i];
+            }
         } else {
             for (int c = 0; c < 3; c++) {
                 for (i = 0; i < 3; i++) {