AudioEncoderPcm16B: Number of bits/sample is 16, not 2

Clearly, this was a case of bit/byte confusion.

BUG=none

Review-Url: https://codereview.webrtc.org/2904883002
Cr-Commit-Position: refs/heads/master@{#18254}

webrtc/modules/audio_coding/codecs/pcm16b/audio_encoder_pcm16b.cc

@@ -84,9 +84,10 @@ rtc::Optional<AudioCodecInfo> AudioEncoderPcm16B::QueryAudioEncoder(
       format.num_channels >= 1) {
     Config config = CreateConfig(0, format);
     if (config.IsOk()) {
+      constexpr int bits_per_sample = 16;
       return rtc::Optional<AudioCodecInfo>(
           {config.sample_rate_hz, config.num_channels,
-           config.sample_rate_hz * 2 *
+           config.sample_rate_hz * bits_per_sample *
                rtc::dchecked_cast<int>(config.num_channels)});
     }
   }