dt-bindings: power: Bindings for Samsung batteries

This adds device tree bindings for Samsung SDI batteries.
Everything can be determined from the product number so the entire
battery is just a specific compatible string.

Cc: devicetree@vger.kernel.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>