arm64: dts: ls1028a: fix FlexSPI clock input

On the LS1028A the FlexSPI clock is connected to the first HWA output,
see Figure 7 "Clock subsystem block diagram".

Fixes: c77fae5b ("arm64: dts: ls1028a: Add FlexSPI support")
Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/fsl-ls1028a.dtsi

@@ -309,7 +309,7 @@ fspi: spi@20c0000 {
 			      <0x0 0x20000000 0x0 0x10000000>;
 			reg-names = "fspi_base", "fspi_mmap";
 			interrupts = <GIC_SPI 25 IRQ_TYPE_LEVEL_HIGH>;
-			clocks = <&clockgen 4 3>, <&clockgen 4 3>;
+			clocks = <&clockgen 2 0>, <&clockgen 2 0>;
 			clock-names = "fspi_en", "fspi";
 			status = "disabled";
 		};