dt-bindings: pinctrl: pinctrl-single: add marvell,pxa1908-padconf compatible

Add the "marvell,pxa1908-padconf" compatible to allow migrating to a
separate pinctrl driver later.

Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Duje Mihanović <duje.mihanovic@skole.hr>
Link: https://lore.kernel.org/20241104-pxa1908-lkml-v13-2-e050609b8d6c@skole.hr


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