pinctrl: s32cc: refactor pin config parsing

Move common codes into smaller inline functions and remove argument checks
that are not actually used by pull up/down bits in the S32 MSCR register.

Signed-off-by: Chester Lin <clin@suse.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20230327062754.3326-3-clin@suse.com


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