arm: dts: ls1028a-rdb: disable DSPI nodes

There is no SPI peripheral on the LS1028A-RDB, therefore no reason to
enable these nodes in the U-Boot device tree (and Linux does not enable
them either).

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Priyanka Jain <priyanka.jain@nxp.com>

arch/arm/dts/fsl-ls1028a-rdb.dts

@@ -24,18 +24,6 @@
 	};
 };
 
-&dspi0 {
-	status = "okay";
-};
-
-&dspi1 {
-	status = "okay";
-};
-
-&dspi2 {
-	status = "okay";
-};
-
 &duart0 {
 	status = "okay";
 };