s302menc: fix bits_per_raw_sample for 21, 22 & 23 case

Signed-off-by: Paul B Mahol <onemda@gmail.com>

libavcodec/s302menc.c

@@ -46,6 +46,7 @@ static av_cold int s302m_encode_init(AVCodecContext *avctx)
         avctx->bits_per_raw_sample = 16;
         break;
     case AV_SAMPLE_FMT_S32:
+        if (avctx->bits_per_raw_sample > 20) {
             if (avctx->bits_per_raw_sample > 24) {
                 av_log(avctx, AV_LOG_WARNING, "encoding as 24 bits-per-sample\n");
             avctx->bits_per_raw_sample = 24;