ASoC: rt5616: add the mclk for the codec driver

This patch adds the code to enable the clock to the CODEC driver
if it needs the clock enabled.

In some case, We need to claim the clock which is driving the codec
so that when we enable clock gating, we continue to clock the codec
when needed.

if mclk provided, to enable and disable the clock source.

Signed-off-by: Caesar Wang <wxt@rock-chips.com>
Signed-off-by: Mark Brown <broonie@kernel.org>