Add out4.ru O4-iMX-NANO board

Board designed for quick prototyping and has one microSD port,
2 Ethernet ports, 2 USB ports, I2C, SPI, CAN, RS-485, GPIO,
UART interfaces, and 2 RGB LEDs.

Signed-off-by: Oleh Kravchenko <oleg@kaa.org.ua>
Cc: Stefano Babic <sbabic@denx.de>
diff --git a/board/out4/o4-imx6ull-nano/Makefile b/board/out4/o4-imx6ull-nano/Makefile
new file mode 100644
index 0000000..a3f4646
--- /dev/null
+++ b/board/out4/o4-imx6ull-nano/Makefile
@@ -0,0 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0+
+# Copyright (C) 2021 Oleh Kravchenko <oleg@kaa.org.ua>
+
+obj-y := o4-imx6ull-nano.o