test/encode/avcenc: Add HRD support in avcenc demo application.
test/encode/avcenc: Add HRD support in avcenc demo application.

Signed-off-by: Zhou Chang <51ad061729f5418fbf57d7f4d13e3e85573c85d5@intel.com>

01org/iotg-lin-gfx-libva,zzhhui/libva,chenxianqin/vaapi-libva,gbeauchesne/libva,gbeauchesne/libva,zzhhui/libva,chenxianqin/vaapi-libva,01org/libva-cros,chenxianqin/vaapi-libva,01org/iotg-lin-gfx-libva,01org/libva-cros,pma1/libva,zzhhui/libva,gbeauchesne/libva,01org/iotg-lin-gfx-libva,01org/libva-cros,pma1/libva,pma1/libva