dm: ls1021a: dts: Update DSPI node to support DM SPI

Update DSPI controller node in ls1021a.dtsi.
Update flash device node in ls1021a-qds.dts.
Ls1021a-twr board doesn't support DSPI, so remove DSPI node
in ls1021a-twr.dts.

Signed-off-by: Haikun Wang <Haikun.Wang@freescale.com>
Acked-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/arm/dts/ls1021a.dtsi b/arch/arm/dts/ls1021a.dtsi
index 064d10c..8b3c557 100644
--- a/arch/arm/dts/ls1021a.dtsi
+++ b/arch/arm/dts/ls1021a.dtsi
@@ -152,7 +152,7 @@
 			interrupts = <GIC_SPI 96 IRQ_TYPE_LEVEL_HIGH>;
 			clock-names = "dspi";
 			clocks = <&platform_clk 1>;
-			spi-num-chipselects = <5>;
+			num-cs = <6>;
 			big-endian;
 			status = "disabled";
 		};
@@ -165,7 +165,7 @@
 			interrupts = <GIC_SPI 97 IRQ_TYPE_LEVEL_HIGH>;
 			clock-names = "dspi";
 			clocks = <&platform_clk 1>;
-			spi-num-chipselects = <5>;
+			num-cs = <6>;
 			big-endian;
 			status = "disabled";
 		};