ARM: dts: at91: gurnard: fix SPI bus unit address

w+arch/arm/dts/.at91sam9g45-gurnard.dtb.pre.tmp:118.21-122.7: Warning (spi_bus_reg): /ahb/apb/spi@fffa4000/mtd_dataflash@0: SPI bus unit address format error, expected "1"
Signed-off-by: NEugen Hristev <eugen.hristev@microchip.com>

arch/arm/dts/at91sam9g45-gurnard.dts

@@ -115,7 +115,7 @@
 
 			spi0: spi@fffa4000 {
 				cs-gpios = <0>, <&pioC 11 0>, <0>, <0>;
-				mtd_dataflash@0 {
+				mtd_dataflash@1 {
 					compatible = "atmel,at45", "atmel,dataflash";
 					spi-max-frequency = <50000000>;
 					reg = <1>;