msdkenc: Enable LowDelayBrc and MaxFrameSize for I/P frame
Enable these features for accurate bitrate control. Feature introduction of LowDelayBRC, MaxFrameSizeI and MaxFrameSizeP could be found here: https://github.com/Intel-Media-SDK/MediaSDK/blob/master/doc/mediasdk-man.md
Signed-off-by: Fan F He fan.f.he@intel.com