VP9: Added support for video size change (scaling down) on inter frames. (#508)

* * rocDecode/VP9: Added support for video size change (scaling down) on inter frames.
 - A new reconfigure mode is added, where we keep the existing VAAPI surfaces and context, and work on the smaller images and store the images in the surfaces.

* * rocDecode/VP9 resize: Added changes based on review comments.

[ROCm/rocdecode commit: 2af7bbf4e7]

projects/rocdecode/src/parser/avc_parser.cpp

@@ -387,6 +387,7 @@ ParserResult AvcVideoParser::NotifyNewSps(AvcSeqParameterSet *p_sps) {
     video_format_params_.display_aspect_ratio.x = disp_width / gcd;
     video_format_params_.display_aspect_ratio.y = disp_height / gcd;
 
+    video_format_params_.reconfig_options = ROCDEC_RECONFIG_NEW_SURFACES;
     if (p_sps->vui_parameters_present_flag) {
         video_format_params_.video_signal_description.video_format = p_sps->vui_seq_parameters.video_format;
         video_format_params_.video_signal_description.video_full_range_flag = p_sps->vui_seq_parameters.video_full_range_flag;