ARM: dts: imx53: add support for USB armory board

Add support for Inverse Path USB armory board, an open source
flash-drive sized computer based on NXP i.MX53 SoC.

https://inversepath.com/usbarmory



Signed-off-by: Andrej Rosano <andrej@inversepath.com>
Tested-by: Vagrant Cascadian <vagrant@debian.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>