pinctrl: nuvoton: Constify wpcm450_groups

There is no modifications are assumed for wpcm450_groups. Constify it.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20231211154239.4190429-1-andriy.shevchenko@linux.intel.com


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