arm64: dts: rockchip: Add missing fan-supply to rk3566-quartz64-a

The Quartz 64 Model-A Schematic from 20210427 on page 7 shows that the
fan's power supply is provided by VCC12V_DCIN.

This fixes the following warning:

  gpio-fan gpio_fan: supply fan not found, using dummy regulator

Signed-off-by: Diederik de Haas <didi.debian@cknow.org>
Link: https://lore.kernel.org/r/20250628142843.839150-1-didi.debian@cknow.org


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