arm64: dts: rockchip: add LEDs for ROCK 4C+

add support for user LEDs on Radxa ROCK 4C+ board.

Signed-off-by: FUKAUMI Naoki <naoki@radxa.com>
Link: https://lore.kernel.org/r/20220908031726.1307105-2-naoki@radxa.com


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