dt-bindings: vendor-prefixes: Add prefix for EBBG

Add a prefix for EBBG. They manufacture displays which are used in some
Xiaomi phones, but I could not find much details about the company.

Signed-off-by: Joel Selvaraj <jo@jsfamily.in>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/BY5PR02MB7009387E1E6C060864C03F87D9DF9@BY5PR02MB7009.namprd02.prod.outlook.com