ARM: dts: mvebu: fix SPI device node

dtc warns about a mismatched address:

arch/arm/boot/dts/armada-385-atl-x530.dts:171.14-199.4: Warning (spi_bus_reg): /soc/spi@10680/spi-flash@0: SPI bus unit address format error, expected "1"

I assume the "reg" property is correct here, so adjust the unit address
accordingly.

Fixes: c6dfc019c239 ("ARM: dts: mvebu: Add device tree for ATL-x530 Board")
Reported-by: Stephen Rothwell <[e-mail]>
Reported-by: kernelci.org bot <[e-mail]>
Signed-off-by: Arnd Bergmann <[e-mail]>

arch/arm/boot/dts/armada-385-atl-x530.dts

···
 	pinctrl-0 = <&spi1_pins>;
 	status = "okay";
 
-	spi-flash@0 {
+	spi-flash@1 {
 		#address-cells = <1>;
 		#size-cells = <1>;
 		compatible = "jedec,spi-nor";