ASoC: mediatek: add mt2701 platform driver implementation.

Add mt2701 platform driver implementation for playback and capture.
The implement follow DAPM structure (memory interface as FE and I2S
as BE).
Because of the hardware design, i2s out required to be enabled when
we need to enable i2s in. This patch includes the implementation.

Signed-off-by: Garlic Tseng <garlic.tseng@mediatek.com>
Signed-off-by: Mark Brown <broonie@kernel.org>