ARM: dts: imx6ul: support Engicam MicroGEA GTW board

Support Engicam MicroGEA GTW board with:

- 256 Mbytes NAND Flash
- 512 Mbytes DRAM DDR2
- Buttons
- LEDs
- Micro SD card connector
- USB 2.0 high-speed/full-speed
- Ethernet MAC

Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>