ARM: dts: rockchip: Add dvs-gpios to rk3288-veyron-jerry

When the rk3288-jerry device tree was first submitted we left out the
dvs-gpios because I pointed out that the property "dvs-gpios" wasn't
yet supported upstream [1].  Soon after that the property was added in
commit bad47ad2 ("regulator: rk808: fixed the overshoot when
adjust voltage").  ...but we forgot to go back and add the property to
the jerry device tree file.  Let's do so now.

NOTE: without this patch, jerry is likely still stable (thanks to the
fallback of making many small jumps in the rk808 regulator code) but
it'll take quite a bit longer to make voltage transitions.

[1] https://lore.kernel.org/linux-arm-kernel/CAD=FV=WwFgjzbk9xF5TU_ie6UnHQMyrZ176D4+jJTWWOoaKC2Q@mail.gmail.com/

Fixes: f3ee390e

 ("ARM: dts: rockchip: add veyron-jerry board")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>