ARM: dts: rockchip: add startup delay to rk3288-veyron panel-regulators

The panels need a bit of time to actually turn on. If this isn't
observed, this results in problems when trying talk to the panels
and thus produces detection errors. 100ms seem to be a safe value
for the time being.

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