dt-bindings: pinctrl: Document Tegra234 pin controllers

Tegra234 contains two pin controllers. Document their compatible strings
and describe the list of pins and functions that they provide.

Signed-off-by: Prathamesh Shete <pshete@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20230605154230.2910847-2-thierry.reding@gmail.com


Signed-off-by: Linus Walleij <linus.walleij@linaro.org>