ARM: dts: rockchip: Pass linux,code to the power key on rk3288-veyron-pinky

According to gpio-keys.yaml, linux,code is a required property.

Pass it to fix the following dt-schema warning:

lid-switch (gpio-keys): key-power: 'linux,code' is a required property

Signed-off-by: Fabio Estevam <festevam@gmail.com>
Link: https://patch.msgid.link/20260323125721.692139-1-festevam@gmail.com
Signed-off-by: Heiko Stuebner <heiko@sntech.de>

Author: fabioestevam

arch/arm/boot/dts/rockchip/rk3288-veyron-pinky.dts

@@ -47,6 +47,7 @@
 
 	key-power {
 		gpios = <&gpio0 RK_PA5 GPIO_ACTIVE_HIGH>;
+		linux,code = <KEY_POWER>;
 	};
 };