Initialize some buffers to 0 when created
Initialize some buffers to 0 when created

Sometimes user doesn't assign a proper value to each field in a buffer
when calling vaRenderPicture(), which will result in random issues
if we want to use these fields in the future. E.g. recently we used
window_size in VAEncMiscParameterRateControl for bitrate control.

Signed-off-by: Xiang, Haihao <8d677183e5993577d4fa73a419b76987913292d6@intel.com>
Reviewed-by: Zhao Yakui <21bae65ecea50a19bd9d0fef489914760189fd5b@intel.com>

01org/iotg-lin-gfx-va-driver,01org/iotg-lin-gfx-va-driver,01org/iotg-lin-gfx-va-driver,01org/iotg-lin-gfx-va-driver,01org/iotg-lin-gfx-va-driver