imx8mn_var_som: Add support for Variscite VAR-SOM-MX8M-NANO board

Add support for iMX8MN VAR-SOM-MX8M-NANO board. Enables support for:

- 1GiB DDR4 RAM
- 16 GiB eMMC
- SD card
- Gigabit ethernet
- USBOTG1 peripheral - fastboot

Signed-off-by: Ariel D'Alessandro <ariel.dalessandro@collabora.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
diff --git a/doc/board/variscite/imx8mn_var_som.rst b/doc/board/variscite/imx8mn_var_som.rst
new file mode 100644
index 0000000..aca881e
--- /dev/null
+++ b/doc/board/variscite/imx8mn_var_som.rst
@@ -0,0 +1,56 @@
+.. SPDX-License-Identifier: GPL-2.0+
+
+imx8mn_var_som
+==============
+
+U-Boot for the Variscite VAR-SOM-MX8MN Symphony evaluation board
+
+Quick Start
+-----------
+
+- Build the ARM Trusted firmware binary
+- Get firmware-imx package
+- Build U-Boot
+- Boot
+
+Get and Build the ARM Trusted firmware
+--------------------------------------
+
+Note: srctree is U-Boot source directory
+Get ATF from: https://github.com/ARM-software/arm-trusted-firmware
+tag: v2.5
+
+.. code-block:: bash
+
+   $ make PLAT=imx8mn IMX_BOOT_UART_BASE=0x30a60000 bl31
+   $ cp build/imx8mn/release/bl31.bin $(srctree)
+
+Get the ddr firmware
+--------------------
+
+.. code-block:: bash
+
+   $ wget https://www.nxp.com/lgfiles/NMG/MAD/YOCTO/firmware-imx-8.9.bin
+   $ chmod +x firmware-imx-8.9.bin
+   $ ./firmware-imx-8.9
+   $ cp firmware-imx-8.9/firmware/ddr/synopsys/ddr4*.bin $(srctree)
+
+Build U-Boot
+------------
+
+.. code-block:: bash
+
+   $ export CROSS_COMPILE=aarch64-linux-gnu-
+   $ make imx8mn_var_som_defconfig
+   $ make
+
+Burn the flash.bin to MicroSD card offset 32KB:
+
+.. code-block:: bash
+
+   $ dd if=flash.bin of=/dev/sd[x] bs=1024 seek=32 conv=notrunc
+
+Boot
+----
+
+Set Boot switch to SD boot
diff --git a/doc/board/variscite/index.rst b/doc/board/variscite/index.rst
new file mode 100644
index 0000000..4186896
--- /dev/null
+++ b/doc/board/variscite/index.rst
@@ -0,0 +1,9 @@
+.. SPDX-License-Identifier: GPL-2.0+
+
+Variscite
+=========
+
+.. toctree::
+   :maxdepth: 2
+
+   imx8mn_var_som