arm64: dts: meson: sm1: add audio devices

Add the audio devices found on the SM1 SoC family. Only the spdif output
and input are missing. These are not supported yet since no platform is
available to them.

Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>