arm64: dts: meson: add audio playback to khadas-vim3l

Add initial audio support limited to HDMI i2s, copying the config
from the existing VIM3 device-tree.

Signed-off-by: Christian Hewitt <christianshewitt@gmail.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
Acked-by: Jerome Brunet <jbrunet@baylibre.com>
Link: https://lore.kernel.org/r/20200718072532.8427-3-christianshewitt@gmail.com