ao_coreaudio_exclusive: do not set ao->bps

This field is basically deprecated or for convenience only, and
this code doesn't need it.

audio/out/ao_coreaudio_exclusive.c

@@ -301,9 +301,6 @@ static int init(struct ao *ao)
         MP_WARN(ao, "stream has non-native byte order, output may fail\n");
 
     ao->samplerate = p->stream_asbd.mSampleRate;
-    ao->bps = ao->samplerate *
-                  (p->stream_asbd.mBytesPerPacket /
-                   p->stream_asbd.mFramesPerPacket);
 
     uint32_t latency_frames = 0;
     uint32_t latency_properties[] = {