arm64: dts: rockchip: remove enable-gpio of backlight on rk3399 evb

There is no enable-gpio for backlight control on rk3399 evb,
actually GPIO1_B5 is for LCD panle enable. So remove it from backlight
dt node.
Signed-off-by: Andy Yan <andy.yan@rock-chips.com>
Link: https://lore.kernel.org/r/20200305113912.32226-4-andy.yan@rock-chips.comSigned-off-by: Heiko Stuebner <heiko@sntech.de>

arch/arm64/boot/dts/rockchip/rk3399-evb.dts

@@ -48,7 +48,6 @@ backlight: backlight {
 			240 241 242 243 244 245 246 247
 			248 249 250 251 252 253 254 255>;
 		default-brightness-level = <200>;
-		enable-gpios = <&gpio1 RK_PB5 GPIO_ACTIVE_HIGH>;
 		pwms = <&pwm0 0 25000 0>;
 	};