dt-bindings: Add vendor prefix for Bticino

Added 'bticino' vendor prefix for Bticino International.
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Signed-off-by: Simone CIANNI <simone.cianni@bticino.it>
Signed-off-by: Raffaele RECALCATI <raffaele.recalcati@bticino.it>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

Documentation/devicetree/bindings/vendor-prefixes.txt

@@ -56,6 +56,7 @@ bosch	Bosch Sensortec GmbH
 boundary	Boundary Devices Inc.
 brcm	Broadcom Corporation
 buffalo	Buffalo, Inc.
+bticino Bticino International
 calxeda	Calxeda
 capella	Capella Microsystems, Inc
 cascoda	Cascoda, Ltd.