lavf/qsvvpp: fix denoise/deinterlace crash in system memory mode

See: ./ffmpeg -init_hw_device qsv=foo -filter_hw_device foo -hwaccel qsv
-f rawvideo -video_size 720x480 -i Test_720x480p.yuv -vf vpp_qsv=denoise=20 -f
rawvideo -y vpp_720x480P_denoise_20.yuv

It is due to the frame is double-freed.
(regression since aef199e:
 lavf/qsv: release the frame in filter_frame).

Signed-off-by: Zhong Li <zhong.li@intel.com>

Author: lizhong1008

libavfilter/qsvvpp.c

@@ -319,7 +319,6 @@ static QSVFrame *submit_frame(QSVVPPContext *s, AVFilterLink *inlink, AVFrame *p
             }
 
             av_frame_copy_props(qsv_frame->frame, picref);
-            av_frame_free(&picref);
         } else
             qsv_frame->frame = av_frame_clone(picref);