dt-bindings: add vendor prefix for Smartlabs LLC

Smartlabs LLC are a professional integrator of Interactive TV solutions
and IPTV/VOD devices [1].

[1] https://www.smartlabs.tv/en/about/



Signed-off-by: Christian Hewitt <christianshewitt@gmail.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20200510124129.31575-2-christianshewitt@gmail.com