ARM: dts: ls1021a: DSPI has 6 chip-selects

Both DSPI have signals SPIn_PCS[0:5] so in summary 6 chip-selects, not 5.
Fix that.
Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/boot/dts/ls1021a.dtsi

@@ -259,7 +259,7 @@ dspi0: dspi@2100000 {
 			interrupts = <GIC_SPI 96 IRQ_TYPE_LEVEL_HIGH>;
 			clock-names = "dspi";
 			clocks = <&platform_clk 1>;
-			spi-num-chipselects = <5>;
+			spi-num-chipselects = <6>;
 			big-endian;
 			status = "disabled";
 		};
@@ -272,7 +272,7 @@ dspi1: dspi@2110000 {
 			interrupts = <GIC_SPI 97 IRQ_TYPE_LEVEL_HIGH>;
 			clock-names = "dspi";
 			clocks = <&platform_clk 1>;
-			spi-num-chipselects = <5>;
+			spi-num-chipselects = <6>;
 			big-endian;
 			status = "disabled";
 		};