Documentation: gpio: Fix reference to gpiod_get_array()

The function is called gpiod_get_array(), not gpiod_array_get().

Fixes: 77588c14 ("gpiolib: Pass array info to get/set array functions")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20190701141005.24631-1-geert+renesas@glider.be


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