arm: ls1021aqds: Enable driver model lpuart serial driver

Convert ls1021aqds_nor_lpuart and ls1021aqds_ddr4_nor_lpuart
to driver model suport. Enable lpuart port driver.

Signed-off-by: York Sun <york.sun@nxp.com>
CC: Alison Wang <alison.wang@nxp.com>
CC: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Alison Wang <alison.wang@nxp.com>
diff --git a/arch/arm/dts/ls1021a-qds-lpuart.dts b/arch/arm/dts/ls1021a-qds-lpuart.dts
new file mode 100644
index 0000000..1d16ffd
--- /dev/null
+++ b/arch/arm/dts/ls1021a-qds-lpuart.dts
@@ -0,0 +1,16 @@
+/*
+ * Freescale ls1021a QDS board common device tree source
+ *
+ * Copyright 2013-2015 Freescale Semiconductor, Inc.
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+/dts-v1/;
+#include "ls1021a-qds.dtsi"
+
+/ {
+	chosen {
+		stdout-path = &lpuart0;
+	};
+};