dt-bindings: vendor-prefixes: add csot

Add "csot" to the Devicetree Vendor Prefix Registry.

Signed-off-by: Langyan Ye <yelangyan@huaqin.corp-partner.google.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20250206131300.1295111-2-yelangyan@huaqin.corp-partner.google.com