avformat/mov: ensure required number of bytes is read

Fixes: use-of-uninitialized-value

Found by OSS-Fuzz.

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavformat/mov.c

@@ -7096,7 +7096,7 @@ static int mov_read_free(MOVContext *c, AVIOContext *pb, MOVAtom atom)
     if (atom.size < 8)
         return 0;
 
-    ret = avio_read(pb, content, FFMIN(sizeof(content), atom.size));
+    ret = ffio_read_size(pb, content, FFMIN(sizeof(content), atom.size));
     if (ret < 0)
         return ret;