arm64: dts: rockchip: Enable PWM FAN for edgeble-neu6b

Add PWM FAN support for Edgeble Neu6B NCM IO board.

Signed-off-by: Jagan Teki <jagan@edgeble.ai>
Link: https://lore.kernel.org/r/20230713143941.1756849-6-jagan@edgeble.ai


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