ARM: dts: ls1021a: fix QuadSPI-memory reg range

According to the Reference Manual, the correct size is 512 MiB.

Without this fix, probing the QSPI fails:

    fsl-quadspi 1550000.spi: ioremap failed for resource
        [mem 0x40000000-0x7fffffff]
    fsl-quadspi 1550000.spi: Freescale QuadSPI probe failed
    fsl-quadspi: probe of 1550000.spi failed with error -12

Fixes: 85f8ee78 ("ARM: dts: ls1021a: Add support for QSPI with ls1021a SoC")
Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/boot/dts/ls1021a.dtsi

@@ -182,7 +182,7 @@ qspi: spi@1550000 {
 			#address-cells = <1>;
 			#size-cells = <0>;
 			reg = <0x0 0x1550000 0x0 0x10000>,
-			      <0x0 0x40000000 0x0 0x40000000>;
+			      <0x0 0x40000000 0x0 0x20000000>;
 			reg-names = "QuadSPI", "QuadSPI-memory";
 			interrupts = <GIC_SPI 131 IRQ_TYPE_LEVEL_HIGH>;
 			clock-names = "qspi_en", "qspi";