According to the struct `mclk_rate_s`, set the default sample rate
to its lowest valid value. This prevents the underlying driver from
setting unsupported values.
Set the mclk frequency on I2S lower half by 1) checking supported
sample rate, data width and mclk multiplier table and 2) setting
this value using the I2S_MCLKFREQUENCY macro. I2S driver may or
may not implement the i2s_mclkfrequency method for setting the
master clock.
Tiago Medicci Serrano