dt-bindings: arm: qcom: Add more sc7180 Chromebook board bindings

This adds board bindings for boards that are downstream but not quite
upstream yet.

Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220520143502.v4.5.Ie8713bc0377672ed8dd71189e66fc0b77226fb85@changeid