ffmpeg: remove trailing whitespace that sneaked into the previous merge

ffmpeg.c

@@ -3861,7 +3861,7 @@ static int process_input(int file_index)
                 pkt.pts -= av_rescale_q(delta, AV_TIME_BASE_Q, ist->st->time_base);
         }
     }
-    
+
     duration = av_rescale_q(ifile->duration, ifile->time_base, ist->st->time_base);
     if (pkt.pts != AV_NOPTS_VALUE) {
         pkt.pts += duration;