Add audio support for the MediaTek Genio 350-evk

Add audio support for the MediaTek Genio 350-evk

Merge series from amergnat@baylibre.com:

This serie aim to add the following audio support for the Genio 350-evk:
- Playback
  - 2ch Headset Jack (Earphone)
  - 1ch Line-out Jack (Speaker)
  - 8ch HDMI Tx
- Capture
  - 1ch DMIC (On-board Digital Microphone)
  - 1ch AMIC (On-board Analogic Microphone)
  - 1ch Headset Jack (External Analogic Microphone)

Of course, HDMI playback need the MT8365 display patches [1] and a DTS
change documented in "mediatek,mt8365-mt6357.yaml".