ASoC: ak4642: enable to use MCKO as fixed rate output pin on DT

ak4642 chip can output clock via MCKO pin as audio reference clock.
This patch supports it on DT

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2 files changed