avfilter/vf_frei0r: fix time when input is realigned

av_frame_copy doesn't copy the input's PTS property, which resulted
in the frei0r filter always receiving the same static time.

Example that has a static distortion without patch:

ffmpeg -filter_complex "testsrc2=s=328x240:d=5,frei0r=distort0r" out.mp4

libavfilter/vf_frei0r.c

@@ -375,6 +375,10 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *in)
         if (!in2)
             goto fail;
         av_frame_copy(in2, in);
+        if (av_frame_copy_props(in2, in) < 0) {
+            av_frame_free(&in2);
+            goto fail;
+        }
         av_frame_free(&in);
         in = in2;
     }