gpiolib: Pass gpio_desc to gpio_set_config()

All callers of gpio_set_config() have to convert a gpio_desc to a
gpio_chip and offset.  Avoid these duplicated conversion steps by
letting gpio_set_config() take a gpio_desc pointer directly.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20200325100439.14000-2-geert+renesas@glider.be


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