ath79: glinet ar150: fix DTC warnings

Supply a unit name to match other .dts files and avoid DTC warnings.

Signed-off-by: Karl Palsson <karlp@etactica.com>

target/linux/ath79/dts/ar9330_glinet_ar150.dts

@@ -89,7 +89,7 @@
 	num-chipselects = <1>;
 	status = "okay";
 
-	spiflash {
+	spiflash@0 {
 		#address-cells = <1>;
 		#size-cells = <1>;
 		compatible = "jedec,spi-nor";