The Q8 tablets use the audio codec to provide audio output via a
headphone jack or a small mono speaker. A GPIO output is used to
control speaker amp.

The tablets may or may not have an internal microphone.
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>