ASoC: mediatek: update clock related properties of MT2701 AFE

Add 'assigned-clocks*' properties which are used to initialize default
domain sources of audio system. we could configure different sets of
input clocks through DTS now. Hence driver no longer cares about that.

Also we change some 'clock-names' to make them more generic so that
other chips can reuse gracefully.

Signed-off-by: Ryder Lee <ryder.lee@mediatek.com>
Signed-off-by: Mark Brown <broonie@kernel.org>