dt-bindings: Add vendor prefix for Catalyst Semiconductor

Add vendor prefix "catalyst" for Catalyst Semiconductor which is
already in use but undocumented.

Signed-off-by: Martyn Welch <martyn.welch@collabora.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>