ARM: dts: rockchip: Specify rk3288-veyron-chromebook's display timings

Let's document the display timings that most veyron chromebooks (like
jaq, jerry, mighty, speedy) have been using out in the field.  This
uses the standard blankings but a slightly slower clock rate, thus
getting a refresh rate 58.3 Hz.

NOTE: this won't really do anything except cause DRM to properly
report the refresh rate since vop_crtc_mode_fixup() was rounding the
pixel clock to 74.25 MHz anyway.  Apparently the adjusted rate isn't
exposed to userspace so it's important that the rate we're trying to
achieve is mostly right.

For the downstream kernel change related to this see See
https://crrev.com/c/324558.

NOTE: minnie uses a different panel will be fixed up in a future
patch, so for now we'll just delete the panel timings there.

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