ARM: dts: imx7-colibri: add support for Toradex Iris carrier boards

Add support for Toradex Iris, small form-factor Pico-ITX Colibri Arm
Computer Module family Carrier Board.

Additional details available at
https://www.toradex.com/products/carrier-board/iris-carrier-board



Signed-off-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>