arm64: dts: rockchip: add thermal fan control to rockpro64

The rockpro64 had a fan node since
commit 5882d65c ("arm64: dts: rockchip: Add PWM fan for RockPro64")
however it was never tied into the thermal driver for automatic control.

Add the links to the thermal node to permit the kernel to handle this
automatically.
Borrowed from the (rk3399-khadas-edge.dtsi).

Signed-off-by: Peter Geis <pgwipeout@gmail.com>
Link: https://lore.kernel.org/r/20210730151727.729822-1-pgwipeout@gmail.com


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