arm64: dts: mediatek: asurada: Add keyboard mapping for the top row

Chromebooks' embedded keyboards differ from standard layouts for the
top row in that they have shortcuts in place of the standard function
keys. Map these keys to achieve the functionality that is pictured on
the printouts.

There's a minor difference between the keys present on Hayato, which
uses an older layout, and Spherion, which uses a newer one.

Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Tested-by: Chen-Yu Tsai <wenst@chromium.org>
Link: https://lore.kernel.org/r/20220629155956.1138955-9-nfraprado@collabora.com


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