pinctrl: spacemit: add support for SpacemiT K1 SoC

SpacemiT's K1 SoC has a pinctrl controller which use single register
to describe all functions, which include bias pull up/down(strong pull),
drive strength, schmitter trigger, slew rate, mux mode.

Signed-off-by: Yixun Lan <dlan@gentoo.org>
Link: https://lore.kernel.org/20241016-02-k1-pinctrl-v5-2-03d395222e4f@gentoo.org


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