Add audio setup for mainline support boards

[superna9999]

Example Scripts:

• https://github.com/LibreELEC/LibreELEC.tv/blob/master/packages/audio/alsa-utils/scripts/soundconfig#L131
• https://github.com/armbian/build/blob/master/packages/blobs/asound.state/asound.state.khadas-vim3
• https://github.com/tobetter/odroid-alsa/blob/master/debian/odroid-alsa.postinst

Alsa Cards:

• https://github.com/tobetter/odroid-alsa/blob/master/usr/share/alsa/cards/G12B-ODROID-N2.conf

Eventually alsa UCM (https://github.com/alsa-project/alsa-ucm-conf)

[superna9999]

#129 was merged in hardknott, should be ported to all newer branches

[superna9999]

#129 has been forward ported into honister, kirkstone & master