arm64: dts: colibri-imx8x: Add SPI

Add Colibri SPI to the board. lpspi2 is being exposed on the SoM edge.
Add settings to the module-level but finally enable it on the eval-board
dtsi.

Signed-off-by: Philippe Schenker <philippe.schenker@toradex.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>