ARM: dts: rockchip: Use interpolated brightness tables for veyron

Use interpolated brightness tables (added by commit 573fe6d1
("backlight: pwm_bl: Linear interpolation between
brightness-levels") for veyron, instead of specifying every single
step. Some devices/panels have intervals that are smaller than
the specified 'num-interpolated-steps', the driver interprets
these intervals as a single step.

Another option would be to switch to a perceptual brightness curve
(CIE 1931), with the caveat that it would change the behavior of
the backlight. Also the concept of a minimum brightness level is
currently not supported for CIE 1931 curves.

Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20191003094137.v2.1.Ic9fd698810ea569c465350154da40b85d24f805b@changeid


Signed-off-by: Heiko Stuebner <heiko@sntech.de>