ARM: dts: rockchip: Remove 0 point from brightness-levels on rk3288-veyron

The extra 0 only adds one point in the userspace visible range,
so this change is almost a noop with the current driver behavior.

We don't need the 0% point, userspace seems to handle this just fine
because it uses the bl_power property to turn off the display.

Furthermore after adding "backlight: pwm_bl: Fix interpolation" patch,
the backlight interpolation will work a little differently. So we need
to preemptively remove the 0-3 segment since otherwise we would have a
252 long interpolation that would slowly go between 0 and 3, looking
really bad in userspace. So it's almost a noop/cleanup now, but it will
be required in the future.

Signed-off-by: Alexandru Stan <[e-mail]>
Reviewed-by: Douglas Anderson <[e-mail]>
Acked-by: Daniel Thompson <[e-mail]>
Link: https://lore.kernel.org/r/20201021220404.v3.1.I96b8d872ec51171f19274e43e96cadc092881271@changeid
Signed-off-by: Heiko Stuebner <[e-mail]>

arch/arm/boot/dts/rk3288-veyron-jaq.dts

···
 
 &backlight {
 	/* Jaq panel PWM must be >= 3%, so start non-zero brightness at 8 */
-	brightness-levels = <0 8 255>;
+	brightness-levels = <8 255>;
 	num-interpolated-steps = <247>;
 };
 

arch/arm/boot/dts/rk3288-veyron-minnie.dts

···
 
 &backlight {
 	/* Minnie panel PWM must be >= 1%, so start non-zero brightness at 3 */
-	brightness-levels = <0 3 255>;
+	brightness-levels = <3 255>;
 	num-interpolated-steps = <252>;
 };
 

arch/arm/boot/dts/rk3288-veyron-tiger.dts

···
 
 &backlight {
 	/* Tiger panel PWM must be >= 1%, so start non-zero brightness at 3 */
-	brightness-levels = <0 3 255>;
+	brightness-levels = <3 255>;
 	num-interpolated-steps = <252>;
 };