dt-bindings: Add rt5033 MFD, Regulator and Charger

Add device tree binding documentation for rt5033 multifunction device, voltage
regulator and battery charger.

Signed-off-by: Jakob Hauser <jahau@rocketmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Lee Jones <lee@kernel.org>
Link: https://lore.kernel.org/r/bff139976865c2a489ab62333d78c4e3179a8eae.1684182964.git.jahau@rocketmail.com