pinctrl: mediatek: Switch to use no-IRQ PM helpers

Since pm.h provides a helper for system no-IRQ PM callbacks,
switch the driver to use it instead of open coded variant.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20231122144744.2222207-1-andriy.shevchenko@linux.intel.com


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