arm64: dts: freescale: sl28: enable LPUART1

Now that the LPUART has support for the LS1028A SoC, also enable it on
our board.
Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/fsl-ls1028a-kontron-sl28.dts

@@ -17,6 +17,7 @@ aliases {
 		crypto = &crypto;
 		serial0 = &duart0;
 		serial1 = &duart1;
+		serial2 = &lpuart1;
 		spi0 = &fspi;
 		spi1 = &dspi2;
 	};
@@ -185,3 +186,7 @@ eeprom@50 {
 		pagesize = <32>;
 	};
 };
+
+&lpuart1 {
+	status = "okay";
+};