devicetree/bindings: Add GCW vendor prefix

devicetree/bindings: Add GCW vendor prefix

Game Consoles Worldwide, mostly known under the acronym GCW, is the
creator of the GCW Zero open-source video game system.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Acked-by: Rob Herring <robh@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Maarten ter Huurne <maarten@treewalker.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/18489/
Signed-off-by: James Hogan <jhogan@kernel.org>