va: Remove user_data from MPEG-2 encoding APIs
va: Remove user_data from MPEG-2 encoding APIs

The application can insert a raw packed header if user data is needed

Signed-off-by: Xiang, Haihao <8d677183e5993577d4fa73a419b76987913292d6@intel.com>

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