armv7: Add support of ls1021a-iot board

The patch adds support for Freescale ls1021a-iot board.

Signed-off-by: Feng Li <feng.li_2@nxp.com>
[YS: rewrite commit message, fix whitespace in Kconfig]
Reviewed-by: York Sun <york.sun@nxp.com>
diff --git a/configs/ls1021aiot_sdcard_defconfig b/configs/ls1021aiot_sdcard_defconfig
new file mode 100644
index 0000000..4b082ab
--- /dev/null
+++ b/configs/ls1021aiot_sdcard_defconfig
@@ -0,0 +1,17 @@
+CONFIG_ARM=y
+CONFIG_TARGET_LS1021AIOT=y
+CONFIG_SPL=y
+CONFIG_DEFAULT_DEVICE_TREE="ls1021a-iot-duart"
+CONFIG_DM_SPI=y
+CONFIG_SYS_EXTRA_OPTIONS="RAMBOOT_PBL,SPL_FSL_PBL,SD_BOOT,SD_BOOT_QSPI"
+CONFIG_CMD_DM=y
+CONFIG_DM=y
+CONFIG_OF_CONTROL=y
+CONFIG_SPI_FLASH=y
+CONFIG_SPI_FLASH_ATMEL=y
+CONFIG_SPI_FLASH_STMICRO=y
+CONFIG_FSL_DSPI=y
+CONFIG_FSL_QSPI=y
+CONFIG_NETDEVICES=y
+CONFIG_E1000=y
+CONFIG_SYS_NS16550=y