board/liteboard: Add support for liteBoard

liteBoard is a development board which uses liteSOM as its base.

Hardware specification:
 * liteSOM (i.MX6UL, DRAM, eMMC)
 * Ethernet PHY (id 0)
 * USB host (usb_otg1)
 * MicroSD slot (uSDHC1)

Signed-off-by: Marcin Niestroj <m.niestroj@grinn-global.com>

configs/liteboard_defconfig

@@ -0,0 +1,29 @@
+CONFIG_ARM=y
+CONFIG_ARCH_MX6=y
+CONFIG_SPL_GPIO_SUPPORT=y
+CONFIG_SPL_LIBCOMMON_SUPPORT=y
+CONFIG_SPL_LIBGENERIC_SUPPORT=y
+CONFIG_TARGET_LITEBOARD=y
+CONFIG_SPL_MMC_SUPPORT=y
+CONFIG_SPL_SERIAL_SUPPORT=y
+CONFIG_SPL_WATCHDOG_SUPPORT=y
+CONFIG_SYS_EXTRA_OPTIONS="IMX_CONFIG=arch/arm/imx-common/spl_sd.cfg"
+CONFIG_BOOTDELAY=1
+CONFIG_DEFAULT_FDT_FILE="imx6ul-liteboard.dtb"
+CONFIG_SPL=y
+CONFIG_HUSH_PARSER=y
+CONFIG_CMD_BOOTZ=y
+# CONFIG_CMD_IMLS is not set
+CONFIG_CMD_MEMTEST=y
+CONFIG_CMD_MMC=y
+CONFIG_CMD_USB=y
+CONFIG_CMD_GPIO=y
+CONFIG_CMD_DHCP=y
+CONFIG_CMD_PING=y
+CONFIG_CMD_CACHE=y
+CONFIG_CMD_EXT2=y
+CONFIG_CMD_EXT4=y
+CONFIG_CMD_EXT4_WRITE=y
+CONFIG_CMD_FAT=y
+CONFIG_CMD_FS_GENERIC=y
+CONFIG_OF_LIBFDT=y