I2S_PDM_TX_CLK_DAC_DEFAULT_CONFIG macro

TX PDM can only be set to the following two up-sampling rate configurations: 1: fp = 960, fs = sample_rate_hz / 100, in this case, Fpdm = 128*48000 2: fp = 960, fs = 480, in this case, Fpdm = 128*Fpcm = 128*sample_rate_hz If the PDM receiver do not care the PDM serial clock, it's recommended set Fpdm = 128*48000. Otherwise, the second configuration should be adopted. The noise might be different with different configurations, this macro provides a set of configurations that have relatively high SNR (Signal Noise Ratio), you can also adjust them to fit your case.