dt-bindings: vendor-prefixes: add Startkit

Starterkit is small vendor of development boards and SoM based on Atmel,
i.MX and Allwinner SoCs.

http://starterkit.ru/html/index.php



Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>