gpio: pca953x: Fix pca953x_gpio_set_pull_up_down()

A previous fix, commit dc87f6dd058a ("gpio: pca953x: Fix
pca953x_gpio_set_config"), identified that pinconf_to_config_param() needed
to be used to isolate the config_param from the pinconf in
pca953x_gpio_set_config(). This fix however did not consider that this
would also be needed in pca953x_gpio_set_pull_up_down() to which it passes
this config.

Perform a similar call in pca953x_gpio_set_pull_up_down() to isolate the
configuration parameter there as well, rather than passing it from
pca953x_gpio_set_config() as the configuration argument may also be needed
in pca953x_gpio_set_pull_up_down() at a later date.

Signed-off-by: Martyn Welch <martyn.welch@collabora.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>