pinctrl: nuvoton: npcm7xx: Constify static ops structs

The only usage of these structs is to assign their address to various
ops fields in the pinctrl_desc struct, which are const pointers. Make
them const to allow the compiler to put them in read-only memory.

Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Link: https://lore.kernel.org/r/20200926202342.31014-1-rikard.falkeborn@gmail.com


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