ASoC: uniphier: add support for UniPhier AIO CPU DAI driver

This patch adds CPU DAI driver for UniPhier AIO audio sound system.

This module provides PCM devices for all input/output port of AIO
such as I2S, S/PDIF.

Signed-off-by: Katsuhiro Suzuki <suzuki.katsuhiro@socionext.com>
Signed-off-by: Mark Brown <broonie@kernel.org>