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: 2cdba9b0 ("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>