The test program is to connect CLK, WS, and SDA lines between the
TX and RX. DAO is the master output, DAI is the slave input. This test
is not a real-world application but test both TX and RX channel in
a single program. 

To use the I2S with the DMA: Set "I2S_DMA_ENABLED" to 1

Example functionality:                                                   
 - Clock Settings:
   - XTAL  =  12 MHz
   - PLL0  = 288 MHz
   - CCLK  =  72 MHz