ARM: dts: rockchip: Switch to builtin HDMI DDC bus on rk3288-veyron

Downstream Chrome OS kernels use the builtin DDC bus from dw_hdmi on
veyron.  This is the only way to get them to negotiate HDCP.

Although HDCP isn't currently all supported upstream, it still seems
like it makes sense to use dw_hdmi's builtin I2C.  Maybe eventually we
can get HDCP negotiation working.

Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Sean Paul <sean@poorly.run>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>