devicetree: bindings: Document CompuLab vendor

Add CompuLab Ltd. to the list of device tree vendor prefixes.

CompuLab manufacturers ARM-based computer-on-module, system-on-module
products, and miniature fanless-PCs.

Acked-by: Igor Grinberg <grinberg@compulab.co.il>
Signed-off-by: Uri Mashiach <uri.mashiach@compulab.co.il>
Signed-off-by: Rob Herring <robh@kernel.org>