ASoC: pcm3168a: The codec does not support S32_LE

24 bits is supported in all modes and 16 bit only when the codec is slave
and the DAI is set to RIGHT_J.

Remove the unsupported sample format.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Link: https://lore.kernel.org/r/20190919071652.31724-1-peter.ujfalusi@ti.com
Signed-off-by: Mark Brown <broonie@kernel.org>