This filter uses ff_set_common_all_samplerates().
Also don't overwrite outlink->sample_rate in config_output;
it is harmless, because it is overwritten with the value it already
had, but it is an API violation.
Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>