avformat/mov: Fix DoS in read_tfra()

Fixes: Missing EOF check in loop
No testcase

Found-by: Xiaohei and Wangchu from Alibaba Security Team
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
static int should_retry(AVIOContext *pb, int error_code) {
    if (error_code == AVERROR_EOF || avio_feof(pb))
        return 0;

    return 1;
}

static int should_retry(AVIOContext *pb, int error_code) {
    if (error_code == AVERROR_EOF || avio_feof(pb))
        return 0;

    return 1;
}
