ffmpeg: add correct field for raw pts in -progress report

PTS is in microseconds, so correct field name is out_time_us.

Old field out_time_ms kept for now - will be removed after a suitable transition
period.

Fixes #7345

fftools/ffmpeg.c

@@ -1794,9 +1794,11 @@ static void print_report(int is_last_report, int64_t timer_start, int64_t cur_ti
     if (total_size < 0) av_bprintf(&buf_script, "total_size=N/A\n");
     else                av_bprintf(&buf_script, "total_size=%"PRId64"\n", total_size);
     if (pts == AV_NOPTS_VALUE) {
+        av_bprintf(&buf_script, "out_time_us=N/A\n");
         av_bprintf(&buf_script, "out_time_ms=N/A\n");
         av_bprintf(&buf_script, "out_time=N/A\n");
     } else {
+        av_bprintf(&buf_script, "out_time_us=%"PRId64"\n", pts);
         av_bprintf(&buf_script, "out_time_ms=%"PRId64"\n", pts);
         av_bprintf(&buf_script, "out_time=%s%02d:%02d:%02d.%06d\n",
                    hours_sign, hours, mins, secs, us);