frontend/va: enhance some rate control features
In h264 and hevc encoding, there are some rate control parameters such as max_frame_size (max_au_size), and filler_data_enable, skip_frame_enable, HRD parameters as well as some picture level rate control parameters. This change is targeting adding these parameters in.
Signed-off-by: Ruijing Dong ruijing.dong@amd.com