arm64: dts: rockchip: Add vcc-supply to SPI flash on rk3566-quartz64-b

The Quartz64 Model B has a Winbound 25Q64DWZPIG SPI flash chip,
identified as 'U13' on the component placement schematic.
In the Quartz 64 Model-B Schematic from 20220124 on page 17, we can see
that the VCC connector is connected to VCCIO_FLASH and page 4 shows that
that in turn is connected to the VCCIO2 domain.
That domain uses vcc_1v8 as its power source.

This fixes the following warning:

  spi-nor spi4.0: supply vcc not found, using dummy regulator

Signed-off-by: Diederik de Haas <didi.debian@cknow.org>
Link: https://lore.kernel.org/r/20250503152917.138648-3-didi.debian@cknow.org
Signed-off-by: Heiko Stuebner <heiko@sntech.de>

arch/arm64/boot/dts/rockchip/rk3566-quartz64-b.dts

@@ -648,6 +648,7 @@ flash@0 {
 		spi-max-frequency = <24000000>;
 		spi-rx-bus-width = <4>;
 		spi-tx-bus-width = <1>;
+		vcc-supply = <&vcc_1v8>;
 	};
 };