dt-bindings: add vendor prefix for Linux Automation GmbH

Linux Automation GmbH[0] was founded in 2019 in order to develop
electronics for embedded Linux. Add its vendor prefix so it may be used
in future board and device compatibles.

[0]: https://www.linux-automation.com



Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Robert Schwebel <rsc@linux-automation.com>
Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Alexandre Torgue <alexandre.torgue@st.com>