arm64: dts: ls208xa-qds: Pass unit name to dspi child nodes

Pass unit name to dspi child nodes to fix the following build warnings
with W=1:

arch/arm64/boot/dts/freescale/fsl-ls2080a-qds.dtb: Warning (unit_address_vs_reg): Node /soc/dspi@2100000/n25q128a has a reg or ranges property, but no unit name
arch/arm64/boot/dts/freescale/fsl-ls2080a-qds.dtb: Warning (unit_address_vs_reg): Node /soc/dspi@2100000/sst25wf040b has a reg or ranges property, but no unit name
arch/arm64/boot/dts/freescale/fsl-ls2080a-qds.dtb: Warning (unit_address_vs_reg): Node /soc/dspi@2100000/en25s64 has a reg or ranges property, but no unit name
Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/fsl-ls208xa-qds.dtsi

@@ -140,21 +140,21 @@ &i2c3 {
 
 &dspi {
 	status = "okay";
-	dflash0: n25q128a {
+	dflash0: n25q128a@0 {
 		#address-cells = <1>;
 		#size-cells = <1>;
 		compatible = "st,m25p80";
 		spi-max-frequency = <3000000>;
 		reg = <0>;
 	};
-	dflash1: sst25wf040b {
+	dflash1: sst25wf040b@1 {
 		#address-cells = <1>;
 		#size-cells = <1>;
 		compatible = "st,m25p80";
 		spi-max-frequency = <3000000>;
 		reg = <1>;
 	};
-	dflash2: en25s64 {
+	dflash2: en25s64@2 {
 		#address-cells = <1>;
 		#size-cells = <1>;
 		compatible = "st,m25p80";