fftools/ffmpeg_filter: configure min_hard_comp unconditionally

There are two issues here. Firstly, the floating-point comparison
is always true. Seconly, the code depends on the default value of
min_hard_comp implicitly, which can be dangerous.

Partially fixes ticket 9859.

Reviewed-by: Anton Khirnov <anton@khirnov.net>
Signed-off-by: Zhao Zhili <zhilizhao@tencent.com>

fftools/ffmpeg_filter.c

@@ -896,7 +896,6 @@ static int configure_input_audio_filter(FilterGraph *fg, InputFilter *ifilter,
         char args[256] = {0};
 
         av_strlcatf(args, sizeof(args), "async=%d", audio_sync_method);
-        if (audio_drift_threshold != 0.1)
         av_strlcatf(args, sizeof(args), ":min_hard_comp=%f", audio_drift_threshold);
         if (!fg->reconfiguration)
             av_strlcatf(args, sizeof(args), ":first_pts=0");