ASoC: rt5670: Fix JD phsh button support issue

We need to set mx-fa bit 3 to 1 to support JD and push button.
It will switch to RC clock automatically once MCLK is not present.
And we separate bias level standby to standby and off. The standby
level provide the necessary power for JD and push button support.

Signed-off-by: Bard Liao <bardliao@realtek.com>