dt-bindings: pinctrl: spacemit: add support for K1 SoC

Add dt-bindings for the pinctrl driver of SpacemiT's K1 SoC.

Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Yixun Lan <dlan@gentoo.org>
Link: https://lore.kernel.org/20241016-02-k1-pinctrl-v5-1-03d395222e4f@gentoo.org


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