gpiolib: remove unnecessary argument from set_config call

Remove unnecessary argument when setting PIN_CONFIG_BIAS_DISABLE. No
argument is expected by pinctrl, so removing it should be harmless.

Fixes: 2148ad77 ("gpiolib: add support for disabling line bias")
Signed-off-by: Kent Gibson <warthog618@gmail.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>