ARM: dts: sun8i-a23: q8-tablet: Enable internal audio codec

The A23 Q8 tablets have an internal mono speaker w/ external amp
which has a shutdown control tied to a GPIO pin. Both the speaker
amp and the headphone jack are tied to the HP output pins. While
the speaker is mono, the headset jack is stereo. Unfortunately
the driver does not support automatic switching of this.

In addition, the headset is DC coupled, or "direct drive" enabled.
The headset's microphone is tied to MIC2 with HBIAS providing power.
A separate internal microphone is tied to MIC1 with MBIAS providing
power.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>