ARM: dts: rockchip: Add device tree for rk3288-veyron-mighty

Mighty is basically the same Chromebook as Jaq but it has a full-sized
SD slot and some different (slightly more rugged) plastics around it.
Like Jaq, Mighty may show up with various different brandings but all
of them have the same board inside.

In the downstream kernel Mighty and Jaq share a "dtsi" and Mighty just
adds the SD write protect (needed for a full-sized SD slot).  We'll do
this upstream by just including the Jaq dts and make the changes.

Signed-off-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>