dt-bindings: arm64: dts: mediatek: Add more SKUs for mt8183 fennel board

Add sku2 and sku7 which uses different audio codec than other fennel boards.

Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>
Link: https://lore.kernel.org/r/20211110063118.3412564-6-hsinyi@chromium.org


Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>