audio: remove unused noop_conv() function

The function audio_capture_mix_and_clear() no longer uses
audio_pcm_sw_write() to resample audio frames from one internal
buffer to another. For this reason, the noop_conv() function is
now unused. Remove it.

Acked-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Volker Rümelin <vr_qemu@t-online.de>
Message-Id: <20230224190555.7409-8-vr_qemu@t-online.de>

audio/audio.c

@@ -381,13 +381,6 @@ void audio_pcm_info_clear_buf (struct audio_pcm_info *info, void *buf, int len)
 /*
  * Capture
  */
-static void noop_conv (struct st_sample *dst, const void *src, int samples)
-{
-    (void) src;
-    (void) dst;
-    (void) samples;
-}
-
 static CaptureVoiceOut *audio_pcm_capture_find_specific(AudioState *s,
                                                         struct audsettings *as)
 {
@@ -485,7 +478,6 @@ static int audio_attach_capture (HWVoiceOut *hw)
         sw->info = hw->info;
         sw->empty = 1;
         sw->active = hw->enabled;
-        sw->conv = noop_conv;
         sw->ratio = ((int64_t) hw_cap->info.freq << 32) / sw->info.freq;
         sw->vol = nominal_volume;
         sw->rate = st_rate_start (sw->info.freq, hw_cap->info.freq);