ASoC: cs42l42: Fix bclk calculation for mono

An I2S frame always has a left and right channel slot even if mono
data is being sent. So if channels==1 the actual bitclock frequency
is 2 * snd_soc_params_to_bclk(params).

Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Fixes: 2cdba9b ("ASoC: cs42l42: Use bclk from hw_params if set_sysclk was not called")
Link: https://lore.kernel.org/r/20210729170929.6589-3-rf@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/cs42l42.c

@@ -830,6 +830,10 @@ static int cs42l42_pcm_hw_params(struct snd_pcm_substream *substream,
 	cs42l42->srate = params_rate(params);
 	cs42l42->bclk = snd_soc_params_to_bclk(params);
 
+	/* I2S frame always has 2 channels even for mono audio */
+	if (channels == 1)
+		cs42l42->bclk *= 2;
+
 	switch(substream->stream) {
 	case SNDRV_PCM_STREAM_CAPTURE:
 		if (channels == 2) {