avcodec/utils: correct align value for interplay

Fixes out of array access
Fixes: 452/fuzz-1-ffmpeg_VIDEO_AV_CODEC_ID_INTERPLAY_VIDEO_fuzzer

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/targets/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
int ff_set_dimensions(AVCodecContext *s, int width, int height)
{
    int ret = av_image_check_size2(width, height, s->max_pixels, AV_PIX_FMT_NONE, 0, s);

    if (ret < 0)
        width = height = 0;

    s->coded_width  = width;
    s->coded_height = height;
    s->width        = AV_CEIL_RSHIFT(width,  s->lowres);
    s->height       = AV_CEIL_RSHIFT(height, s->lowres);

    return ret;
}

int ff_set_dimensions(AVCodecContext *s, int width, int height)
{
    int ret = av_image_check_size2(width, height, s->max_pixels, AV_PIX_FMT_NONE, 0, s);

    if (ret < 0)
        width = height = 0;

    s->coded_width  = width;
    s->coded_height = height;
    s->width        = AV_CEIL_RSHIFT(width,  s->lowres);
    s->height       = AV_CEIL_RSHIFT(height, s->lowres);

    return ret;
}
