dt-bindings: pinctrl: Add pinctrl for Sophgo SG2042 series SoC

dt-bindings: pinctrl: Add pinctrl for Sophgo SG2042 series SoC

SG2042 introduces a simple pinctrl device for all configurable pins.
For the SG2042 pinctl register file, each register (32 bits) is
responsible for two pins, each occupying the upper 16 bits and lower
16 bits of the register. It supports setting pull up/down, drive
strength and input schmitt trigger.

Add support for SG2042 pinctrl device.

Signed-off-by: Inochi Amaoto <inochiama@gmail.com>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://lore.kernel.org/20250211051801.470800-6-inochiama@gmail.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>