Unexpected I2S data output

[dannyhui-xmos]

There is a constant output (0xA5A5A5A5) from I2S_DOUT pin after the FFD system up.

Finding:

1. FreeRTOS kernel set the default value of the stack to tskSTACK_FILL_BYTE (0xa5U) for water level checking
2. The function i2s_ratio_n from modules/io/modules/i2s/src/i2s_master.c:79 haven't initialized/cleared the default value of the variable out_samps.

Suggested Fix:
Initialize the variables before use
memset(in_samps, 0, sizeof(in_samps));
memset(out_samps, 0, sizeof(out_samps));

Testing Kit: XK-VOICE-L71