This adds support for the OMNIA Flex Concentrator product
from Kamstrup A/S. It's providing radio mesh communication
infrastructure for smart electricity meters.

Kamstrup OMNIA is a modular and scalable smart grid platform.
Signed-off-by: Bruno Thomsen <bruno.thomsen@gmail.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>