gpiolib: Remove unused gpio_chip parameter from gpio_set_bias()

gpio_set_bias() no longer uses the passed gpio_chip pointer parameter.
Remove it.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20200325100439.14000-3-geert+renesas@glider.be


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