pinctrl: cs42l43: Use str_high_low()

Use str_high_low() rather than open coding.

Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20240129153138.3221604-3-ckeepax@opensource.cirrus.com


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