Add dt-bindings for the pinctrl driver of SpacemiT's K1 SoC.
Signed-off-by: Yixun Lan <dlan@xxxxxxxxxx>
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Changes in v3:
- drop spacemit,slew-rate-{enable,disable} property
- use drive-strength instead of drive-strength-microamp
- fold strong-pull-up into bias-pull-up
- format fixed
- title fixed