arm64: dts: meson: gxbb-kii-pro: add initial audio support

Add initial support for HDMI and S/PDIF audio output.

Signed-off-by: Christian Hewitt <christianshewitt@gmail.com>
Tested-by: Ferass El Hafidi <vitali64pmemail@protonmail.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20230306121351.1606360-4-christianshewitt@gmail.com


Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>