arm: ls1021atwr: Enable driver model lpuart serial driver

Convert ls1021atwr_nor_lpuart to driver model support. As a start,
enable lpuart serial port driver.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Alison Wang <alison.wang@nxp.com>
Tested-by: Alison Wang <alison.wang@nxp.com>
Acked-by: Simon Glass <sjg@chromium.org>

arch/arm/dts/Makefile

@@ -93,7 +93,7 @@ dtb-$(CONFIG_TARGET_BEAGLE_X15) += am57xx-beagle-x15.dtb
 dtb-$(CONFIG_TARGET_STV0991) += stv0991.dtb
 
 dtb-$(CONFIG_LS102XA) += ls1021a-qds.dtb \
-	ls1021a-twr-duart.dtb
+	ls1021a-twr-duart.dtb ls1021a-twr-lpuart.dtb
 dtb-$(CONFIG_FSL_LSCH3) += fsl-ls2080a-qds.dtb \
 	fsl-ls2080a-rdb.dtb
 dtb-$(CONFIG_FSL_LSCH2) += fsl-ls1043a-qds.dtb \

arch/arm/dts/ls1021a-twr-lpuart.dts

+/*
+ * Freescale ls1021a TWR board device tree source
+ *
+ * Copyright 2013-2015 Freescale Semiconductor, Inc.
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+/dts-v1/;
+#include "ls1021a-twr.dtsi"
+
+/ {
+	chosen {
+		stdout-path = &lpuart0;
+	};
+};

configs/ls1021atwr_nor_lpuart_defconfig

 CONFIG_ARM=y
 CONFIG_TARGET_LS1021ATWR=y
+CONFIG_DM_SERIAL=y
+CONFIG_DEFAULT_DEVICE_TREE="ls1021a-twr-lpuart"
 CONFIG_SYS_EXTRA_OPTIONS="LPUART"
 # CONFIG_CMD_SETEXPR is not set
+CONFIG_OF_CONTROL=y
+CONFIG_DM=y
 CONFIG_NETDEVICES=y
 CONFIG_E1000=y
 CONFIG_FSL_LPUART=y