imx: Add variscite DART-6UL Evaluation Kit

Port for the DART-6UL Evaluation Kit SBC. Based on the variscite
DART-6UL iMX6ULL SoM.

CPU:   Freescale i.MX6ULL rev1.1 900 MHz (running at 396 MHz)
CPU:   Commercial temperature grade (0C to 95C) at 43C
Reset cause: POR
Model: Variscite DART-6UL Evaluation Kit
Board: Variscite DART-6UL Evaluation Kit
DRAM:  512 MiB
MMC:   FSL_SDHC: 0, FSL_SDHC: 1
In:    serial@02020000
Out:   serial@02020000
Err:   serial@02020000
Net:   FEC0

Working:
 - Eth0
 - i2c
 - MMC/SD
 - eMMC
 - USB host
 - UART 1

Note: LCDIF porting needs DM_VIDEO
https://lists.denx.de/pipermail/u-boot/2019-April/365506.html

Signed-off-by: Parthiban Nallathambi <parthitce@gmail.com>
diff --git a/board/variscite/dart_6ul/README b/board/variscite/dart_6ul/README
new file mode 100644
index 0000000..d76b997
--- /dev/null
+++ b/board/variscite/dart_6ul/README
@@ -0,0 +1,41 @@
+How to use U-Boot on variscite DART-6UL Evaluation Kit
+------------------------------------------------------
+
+- Configure and build U-Boot for DART-6UL iMX6ULL:
+
+    $ make mrproper
+    $ make variscite_dart6ul_defconfig
+    $ make
+
+  This will generate SPL and u-boot-dtb.img images.
+
+Boot from MMC/SD:
+- The SPL and u-boot-dtb.img images need to be flashed into the micro SD card:
+
+    $ sudo dd if=SPL of=/dev/mmcblk0 bs=1k seek=1; sync
+    $ sudo dd if=u-boot-dtb.img of=/dev/mmcblk0 bs=1k seek=69; sync
+
+- Boot mode settings:
+
+  Boot switch position: SW1 -> 0
+			SW2 -> 0
+
+Boot from eMMC:
+- if bootpart is not enabled by default, to enable under Linux
+	echo 0 >/sys/block/mmcblk1boot0/force_ro
+	mmc bootpart enable 1 1 /dev/mmcblk1boot0
+
+- Flash the SPL and u-boot-dtb.img to mmcblk1boot0
+    $ sudo dd if=SPL of=/dev/mmcblk1boot0 bs=1k seek=1; sync
+    $ sudo dd if=u-boot-dtb.img of=/dev/mmcblk1boot0 bs=1k seek=69; sync
+
+- Boot mode settings:
+
+  Boot switch position: SW1 -> 0
+			SW2 -> 1
+
+- Connect the Serial cable to UART0 and the PC for the console.
+
+- Insert the micro SD card in the board and power it up.
+
+- U-Boot messages should come up.